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Lenovo Tab3 8" (2016) Custom Recovery / or any modern Tablet in UK under £100

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Lister Of Smeg

Senior Member
May 20, 2013
698
232
Hi @Tzul / All,

You got me all excited when I saw you had created the custom recovery for the Lenovo Tab3... only to find out that Lenovo have another Tablet called the Tab3 that came out later this year, and it was this one that I was interested in getting.

The Tablet has a model No: ZA170136GB

Any idea if it is possible to create a custom recovery for this too?? Or does anyone know a decent Tablet in the UK for under £100, that has a Custom Recovery, and some fairly recent roms for it...

Mainly need the recovery to backup the current rom, and once I have set the Tablet up for my father, to make an image of that too...

Cheers, Lister
 

Lister Of Smeg

Senior Member
May 20, 2013
698
232
Hi @Tzul / All,

Just found this link, not sure if its for the same (newer Tablet) just the smaller 7" version, instead of the 8" version. But it mentions Android 6.0x which is the default OS on the newer Tablet.

https://webcache.googleusercontent....or-lenovo-tab3.html+&cd=7&hl=en&ct=clnk&gl=uk

The only thing I can't work out, is what the model number is for the newer 2016 8" model, as I've been told its "ZA170136GB" which seems a bit long... Where as most like the 7" version appears to be just "TB3-730X" and makes sense.

Cheers, Lister
 

Tzul

Senior Member
Jun 25, 2014
421
430
Lenovo has quite a few tablets called "Tab3" / "TB3". There are at least 4 or 5 different versions of 7 inch models. Plus 8 inch and 10 inch models.

As far as I know, all of them are based on MediaTek chips, meaning if you need to create and restore backups of entire partitions, you don't even need a custom recovery, as you can use the MediaTek SmartPhone Flash Tool (SPFT) for that. However, in order to use the SPFT, you'll need a "scatter file" that matches the device in question. The scatter file contains details about the device's partitioning (start addresses, sizes, and more). You can create one manually, taking an existing one from a similar device as template, but that requires some specific knowledge and experience.

Creating a custom recovery isn't easy either, particularly if you don't have the device in question at hand. For starters, you need an existing firmware update or backup (e.g. a readback made with the SPFT), from which some required data can be extracted.
 

Lister Of Smeg

Senior Member
May 20, 2013
698
232
Hi @Tzul,


Corr, they don't like to make it easy for their users... do they!!! There's even more than I first suspected then, talk about confusing!!! :( lol
Yeah this one I've spotted is also a MediaTek chipset too...

Does this SPFT tool belong to Lenovo/MediaTek, or apply to many different hardware configurations? Where would I obtain a Scatter file for this Tablet? I've done a bit more Google'ing, and think the unit could be a TB3-850F (although that links to an American version of the one Ive seen in the UK). Its a fairly good Tablet as it is anyway, so do you think its best just to get it anyway, and hope development / support comes for it at a later date??

Once I get the Tablet, I would be able to know what the EXACT model is for sure then... If so, is there anything I can do, in the way of dumping a rom... I believe I may of found the official rom for it on Lenovo's website earlier today at work too. So maybe able to get a rom dump that way...

If I could, do you think it would be possible to make a TWRP based on the Recovery.IMG dumped from the rom.... Or do you still need the device to actually develop and test on...??

Just wonna try get a good Tablet, that I can then create a backup/image of stock build (inc TWRP recovery) and one that I've customised App-wise for my dad to use and back that up. So if he messes it up, I can restore it quickly...

Many thanks for getting back to me so promptly, and so detailed reply.

Cheers, Lister
 
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Tzul

Senior Member
Jun 25, 2014
421
430
The SPFT software is by MediaTek and generally works with all MediaTek-based phones and tablets - provided you have a suitable scatter file.
Once you have the tablet, it should be easy to determine the exact type by going to the Android system settings, about the tablet, and check the values there; primarily model and build number. It should also be on the packaging.

I can build TWRP without owning the tablet, but it's more difficult that way as I basically have to do it "blind". I have done it for the TB3-710I, because a firmware dump was available, and someone provided me with all the info I needed. I guess I could do it for the TB3-850F as well, if I find the time and have all necessary data.
 

Lister Of Smeg

Senior Member
May 20, 2013
698
232
Is that the same tool that would or could be used, if ever I wish to factory reset it (if can't get TWRP onto it) or do you think Lenovo have another method, if things go really screwy?? lol

As for the model, I shall certainly be picking it up tomorrow... As I've spent many-a-days now trying to find an ideal one for my dad, and this one comes in really cheap esp for the spec. So if TWRP can go on it, it will make it an even bigger BONUS... :) :D

So will find out tomorrow what the exact model is, I'm hoping it will be a TB3-850F... As did a bit of Google'ing from the 7" model, came across that model for the 8" which appears to be exactly the same as the UK model... The website is the same, except the cpu seems to be 300mhz faster.. Im sure the UK model is 1GHz, where as they USA is 1.3GHz. Hopefully so, as that will be easier for you too I'm guessing, as it looks like you already have the Scatter file in the other forum... :) or at least a close template, with luck..

I'll do my best to get what ever, and as much info to you as possible... And really really appreciate any efforts you could spare to try and get TWRP on it. No worries if you can't and appreciate you're busy with other things in your life, so absolutely no rush... As said, any effort at all is really appreciated!!! :D

Thank you for even taking the time to read and reply to my request/info... thanks :)

Cheers, Lister
 

Lister Of Smeg

Senior Member
May 20, 2013
698
232
Hi @Tzul,

Ok, I picked the Tablet up from the shop yesterday for my dad and although we've not unboxed it yet. It is indeed the same model you appeared to be helping the use in the thread here. TB3-850F

Hopefully I'll be on it tonight, to find out more information. It appears there are at least 3 or 4 different models sold, WiFi and LTE versions, and they differ from USA to UK.

The USA version features a QuadCore 1.3 Ghz CPU
The UK vesion features a QuadCore 1.0 Ghz CPU

So not sure if that's gonna cause issues, I'll run some software on it tonight to find out the exact CPU inside it... (I have the UK version, 1.0 Ghz... if thats any use?)

I'm also gonna try ask Lenovo (not expecting a speedy response from that company, if I'm honest) to see if they have a factory restore image/tool.... Like all Samsung phones/Tablets have, and even the Tesco's Hudl. They should make it easy for end users to restore their devices, should disaster occur...

If can get a firmware dump, that may help in getting the Boot.Img and Recovery.Img in order to help make a TWRP. As that will be the preferred way of backing up and restoring the device... ;)

How would one flash this to the Tablet, if it's possible...?? Through ADB fastboot?? What's the risk factor of BRICKING the device, outta of 100% say...? Such as Samsung have a Download Mode (which seems they are indestructible) and can always force a stock rom too them...

Cheers, Lister
 

Tzul

Senior Member
Jun 25, 2014
421
430
I doubt that the CPU frequency differs between the US and UK version. They should be exactly the same. I wouldn't trust the info on websites. For my Tab 2 A10-70F, figures differed as well (some sources said 1.5 GHz, others 1.7 GHz; but in reality, it's 1.69 GHz).
Typically, the back of the box should list the correct specs. Does it say anything about the used MediaTek chip (MTxxxx)?

You can use the fastboot flash command to flash at least some partitions, but you might have to "unlock" the bootloader first (there should be an option in the Android developer settings). Alternatively, I can easily patch the bootloader to allow fastboot flash, but in order to install the patched bootloader, you need the SPFT or TWRP.
If you mess up something, you'll "brick" the tablet, but with the SPFT you can almost always restore the firmware.
 
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Lister Of Smeg

Senior Member
May 20, 2013
698
232
Hi @Tzul,

Yeah, was just going via what the website says for both devices. Seems a little silly to change the builds, for different parts of the world. Prolly the same CPU and then either under or overclocked in various regions.

Just got home, and on the back of the box it says... CPU: MT8161P QC 1.0GHZ 64Bit

I'll have to wait an hour or so, as my dad is round our elderly neighbours house helping him out. But when he is back, I'll open the Tablet with him, then enable the "Android Developer Settings" through double/tapping the Build No 7x times. Once I'm in there, I assume it's "USB Debugging" you want me to enable/turn on...??

How will I know if the Bootloader is locked / unlocked? Is there a command / test, to fastboot the device and see if it responds, says anything back?? I don't know much about Fastboot, as my my flashing experience is either done through programs/utilities of via the device itself... Is there anyway to pull the Boot.Img / Recovery.Img via Fastboot?? Or is that done via that SPFT app...?

So you saying, no matter what happens/goes wrong... I can pretty much restore/recover it like Factory via the use of SPFT... There will always be a way to PUSH a firmware to the device???

I'm fully use to using Odin (not sure if you know/aware/used that App) but if SPFT is anything like that... I know that Samsung is almost indestructible via flashing with Odin... Is SPFT the same???

I'm trying to contact Lenovo to see if they have a Factory Image, or process to see if they can have a Restore Image too... That way maybe able to pull those partition from the image file?? ;)

Cheers, Lister
 

Tzul

Senior Member
Jun 25, 2014
421
430
Just got home, and on the back of the box it says... CPU: MT8161P QC 1.0GHZ 64Bit
Thanks, that's what I expected. The actual CPU frequency might be 988 MHz, but rounded up it's 1.0 GHz. ;)

Once I'm in there, I assume it's "USB Debugging" you want me to enable/turn on...??
USB debugging is required for ADB, which is a useful tool. But I was thinking about the option "OEM unlocking - Allow the bootloader to be unlocked", which might or might not be present in the developer menu on your tablet.

How will I know if the Bootloader is locked / unlocked? Is there a command / test, to fastboot the device and see if it responds, says anything back?? I don't know much about Fastboot, as my my flashing experience is either done through programs/utilities of via the device itself... Is there anyway to pull the Boot.Img / Recovery.Img via Fastboot?? Or is that done via that SPFT app...?
Strictly speaking, a locked bootloader performs integrity checks and refuses to start the system when it was tampered with. A locked system wouldn't boot an unofficial boot.img or recovery.img (such as TWRP). That's rarely the case with MediaTek-based devices, i.e. they are usually "unlocked". However, they often have the fastboot flash command restricted/disabled, meaning you can't use fastboot to flash TWRP or other stuff, until you "unlock" the bootloader, or use a patched bootloader.

To make backups of boot.img, recovery.img, etc. you can use the SPFT or a custom recovery. Or you can do it from within Android, provided you have root.

I suggest you first try this:
Open an ADB shell (USB debugging enabled, tablet running Android connected to PC via USB), or use a terminal app, then type
Code:
getprop ro.build.version.incremental
getprop ro.product.ota.model
and tell me the output. I might be able to use that information to find Lenovo's official firmware packages for your tablet.
For my TB3-710F for example, the values are ro.build.version.incremental=Lenovo_TB3-710F_S000026 and ro.product.ota.model=LenovoTB3-710F_L.

Furthermore, boot the tablet by pressing and holding power+volume_up. That should either display a little boot menu ("normal, recovery, fastboot"), or take you directly to the recovery. In the former case, choose "fastboot", in the latter case, the recovery menu should have a "reboot to bootloader" entry at the bottom.
That should take you into fastboot mode. Connect the tablet to PC via USB, and use a fastboot client to run "fastboot getvar all". That'll dump a lot of info, including partition info, which could help with creating a scatter file.
With "fastboot reboot" you can leave fastboot mode.

So you saying, no matter what happens/goes wrong... I can pretty much restore/recover it like Factory via the use of SPFT... There will always be a way to PUSH a firmware to the device???
Yes, if you have a complete firmware backup including scatter file.
The MediaTek SPFT is comparable to Samsung's Odin, except that it also allows to make backups (readbacks). But again, you always need a proper scatter file first. You might be interested in reading this.
 
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Lister Of Smeg

Senior Member
May 20, 2013
698
232
Hi @Tzul,

First of all, Wow... oh WOW!!!! Are you an Android developer, as in OS specialist.... that post was epic in both detail and knowledge. Wow, you really know you're stuff... Do you work for a big company, or just a very clever/gifted hobbyist?? WOW :D Thanks for pointing me to that post, very interesting and giving me a heads up in the process of Lenovo architecture...

Ok, I've unboxed dad's Tablet (he doesn't know this yet... LOL). Turned it on, wow... what an experience, this is the best Android/Tablet (and we've had several over the years, from ZTE phones... to Samsung phones and HP/Tesco Hudl Tablets)... Beautiful experience! :)

Ok,

1) I've enabled Developer Tools (tapped Build No 7x times)

2) I've enabled [ADB Debugging]

3) I've turned on / enabled "OEM Unlocking".
Will this trigger Lenovo software to feel it's been tampered with? Or will it just be normal and allows the bootloader to passthrough / flash a modified recovery to it?

4) getprop ro.build.version.incremental = TB3-850F_S100025_160608_ROW
getprop ro.product.ota.model = LenovoTB3-850F_ROW

5) I couldn't do the Power button + Holding Volume Up button, as when holding both down... The Tablet keeps rebooting, and not loading anything up other than the Lenovo logo, then reboots again...

So I tried Power button + Holding Volume Down button, and it appears to show a menu... But it was ALL in Chinese, other than the word eMMC. I had no idea how to get out of it, other than holding "Vol Up and Power button" as I found from previous, it just boots/reboots loop until let go. I did so, then it said something about SD.. and the rest in Chinese and made a loud beep, before rebooting...

So not sure if I've done anything to an SD Card, internal...?? As we've not put in an external one yet...

So not sure how to get into Bootloader / Recovery yet? As it keeps restarting... :(

Interestingly, when I first turned this device on and connected it to the network, it wants to pull down a small update....

TB3-850F_S100025_160608_ROW_TO_TB3-850F_S100026_160923_ROW
What it currently is...
What it wants to go too...
The update is only 22Mb in size....

I hope this helps?

Cheers, Lister
 
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Tzul

Senior Member
Jun 25, 2014
421
430
My job doesn't really involve Android, but I've studied this, more or less.
Glad to hear that the tablet is good. I'm still satisfied with my Tab 2 as well.

3) I've turned on / enabled "OEM Unlocking".
Will this trigger Lenovo software to feel it's been tampered with? Or will it just be normal and allows the bootloader to passthrough / flash a modified recovery to it?
The latter, as far as I know.

Thanks for the property values. With those, I could find the small update you mentioned. Unfortunately it doesn't contain a complete boot.img file, but at least it contains a barebones scatter file (just the partition start addresses):
Code:
preloader 0x0
pgpt 0x0
proinfo 0x80000
nvram 0x380000
protect1 0x880000
protect2 0x1280000
lk 0x1c80000
para 0x1d00000
boot 0x1d80000
recovery 0x2d80000
logo 0x3d80000
expdb 0x4580000
seccfg 0x4f80000
oemkeystore 0x5000000
secro 0x5200000
keystore 0x5800000
tee1 0x6000000
tee2 0x6500000
frp 0x6a00000
nvdata 0x6b00000
metadata 0x8b00000
system 0xb000000
cache 0xcb000000
userdata 0xe5800000
flashinfo 0xFFFF0084
sgpt 0xFFFF0004
Exactly the same values I used for the preliminary scatter file that you found on the Lenovo forums.
If you like, you can try to use it with the SPFT to make a readback.
Download the latest SPFT, unzip it, find its "option.ini" file, open it, and at the very end change "ShowByScatter=false" to "ShowByScatter=true".
Download and install the USB Preloader driver (cdc-acm).
Finally, run the SPFT, load my scatter file, and make a readback.

5) I couldn't do the Power button + Holding Volume Up button, as when holding both down... The Tablet keeps rebooting, and not loading anything up other than the Lenovo logo, then reboots again...
If you hold down the power button for too long, the tablet will probably reboot.
Try this: Shut down the tablet. Hold volume up, then hold power. When the screen turns on, release the power button, but keep holding volume up.
That should take you to the boot menu or recovery. If not, you can still try to get there via "adb reboot recovery" or "adb reboot-bootloader" (for fastboot).

So I tried Power button + Holding Volume Down button, and it appears to show a menu... But it was ALL in Chinese, other than the word eMMC. I had no idea how to get out of it, other than holding "Vol Up and Power button" as I found from previous, it just boots/reboots loop until let go. I did so, then it said something about SD.. and the rest in Chinese and made a loud beep, before rebooting...
Yeah, on these MediaTek-based devices, that key combination usually takes you to the factory test menu. Avoid going there, you could mess something up.
The bottom-most menu entry gets you out of there (reboot). The menu entry with "eMMC" is "wipe eMMC" - sounds as if it would delete the entire internal flash memory (the eMMC chip), but in actuality, it just does as factory reset, i.e. it only wipes the /data partition (where all user apps and settings are stored). At least it's like that on every device I've tested so far.
 

Lister Of Smeg

Senior Member
May 20, 2013
698
232
Hi @Tzul,

Well, ya certainly know what ya talking about... was a great read. I am technically minded. I do (and have done for about 15/20 years) IT Support. I understand the talk, sometimes we all gotta re-learn new tricks... :)

Ok, you'll love this... I spoke to Lenovo today... Actually very good support really, much better than when we phone up about PCs not working in our company. Anyway, they were still unable to help me with the Tablet.

I spoke to them about not being able to get into Recovery / Bootloader. Didnt tell them why of course, but explained that I wanted to know if there was an official firmware I could download if I wished to return the Tablet to fully stock without any Apps. Blamed my dad messing it up, which is kinda true... even though he has not touched it yet. Anyway, they talked me through many things, BASICALLY WHAT YOU'VE ALREADY TOLD ME.... About holding down Vol Up and Power button. After many attempts, still not working. So I said there is a 22mb update pending, I'll try that and see if that allows me to do the key combo... Still no joy. He told me to do a factory reset in the Android OS (which I knew anyway). And so did that, and sure enough it wiped everything, even Developer Settings. However after re-enabling it again, the OEM Bootloader was STILL UNLOCKED? lol.

Anyway, needless to say... I still cannot get into recovery on this device, and he seems certain I should be able too. He thinks the device may be faulty, and suggests returning it... Apart from not being able to get into Recovery, I dont think it is faulty as seems fine everywhere else.

I also tried "Lenovo Smart Assistant" as it seems that can download firmware from there site. After spending a couple of hours trying to get all the (10x different Android device drivers installs, MTP, ADB, MIDI, blah blah) it still didnt automatically detect in their Smart App. So I tried to select the "Dead Device" mode, where you have to enter "Model No" and Hardware ID, typed in various things... but neither showed up the Tablet??? lol

Anyway, going back to above....

1) Installed the suggested signed drivers for the PreLoader

2) Downloaded, edited Options.ini and ran the latest SPFT

3) Opened the Scatter file, nice to see all the partitions.

4) Tried to do a ReadBack of just Boot.img and Recovery.img but nothing downloaded or seemed to happen. But was doing this in a hurry on my lunch break. Shall have another go at home, or back at work tomorrow.

Ah, think I've seen where I went wrong... I didnt double click on the [File] column. I just assumed the path was already correct, looking at it. Also, can't remember the state of the device, think that was also on at the time. So will have a proper go later... and upload the boot.img and recovery.img

-- Just out of interest, if I was making a STOCK ROM backup. What partitions do I need to select / include / tick, for that??

And assume if I wanted to restore it, just do the exact same. Select the partitions, select the files in the [File] tab as to what I want to restore and use DOWNLOAD only mode? Or would it be best just to make the backups in TWRP once/if it's possible...??


As I'm having no joy with the key combo, I'm gonna try the ADB commands in a sec, and let you know how those go.... :)

Yeah, I wont be going there again in a hurry... Didnt have a clue what any of it was, and it wasn't clear at the time how to get out of it either... :( Sadly I selected the very first open, no idea what that was / is ???? but couldn't get out of it either and had to wait till it finished... :(

I saw eMMC and panicked, as I have 3x Samsung devices that all suffer from the eMMC brickbug issue. Where the chip dies if using a faulty kernel. Thankfully this kernel is all but disappeared, as only came about in an official LEAKED Samsung build. And all previous/after official kernels and all custom kernels had this faulty switch removed... ;) But whenever I see eMMC, I worry now... :( lol

Many thanks, Lister
 

Lister Of Smeg

Senior Member
May 20, 2013
698
232
Hi @Tzul,

Well, after my chat to Lenovo and doing some more testing last night... I think my Tablet could be genuinely faulty...

You know I said how I can't enter Recovery (Power & Vol Up) despite you and Lenovo saying that it should work. Well Lenovo think and said it could be faulty and return to place of purchase.

I tried the ADB commands last night, the Reboot Bootloader worked and sent me into Fastboot. However the Reboot Recovery gives me this error...

no-command-screen-with-dead-android.jpg


Which I am wondering if I don't have a Recovery or it's corrupted...??

I am also failing to get those ReadBacks of either Boot.img or Recovery.img, as depsite having the Tablet off and clicking on the file names, and pointing it where to save. Nothing appears to happen, no data transfers...?? :(

Do you think I'll be able to get those files if I root the device, and use a Root File Manager???

Also, without any official firmware from Lenovo yet... If I root it, will I be able to unroot it by just doing a simple "Factory Reset" within Android OS, or does this keep the root do you know?? Never really used Factory Reset, as always wipe the device in a custom recovery....

Cheers, Lister
 

Tzul

Senior Member
Jun 25, 2014
421
430
You know I said how I can't enter Recovery (Power & Vol Up) despite you and Lenovo saying that it should work. Well Lenovo think and said it could be faulty and return to place of purchase.
That sounds quite unlikely to me. Have you tried what I wrote before? Start holding the volume up button before you turn on the tablet. Then press the power button to turn it on, release the power button again, but keep holding volume up all the time.

I tried the ADB commands last night, the Reboot Bootloader worked and sent me into Fastboot. However the Reboot Recovery gives me this error...
That's not an error, that is in fact the stock recovery! The menu is missing, but that's normal for some devices. There's a "secret" key combination you need to press to activate the menu. Try power+volume up again (or to be more specific, hold down the power button, then "click" the volume up button, then release the power button; do not hold down the power button for 10 seconds or longer, that'll probably reboot the tablet).


I am also failing to get those ReadBacks of either Boot.img or Recovery.img, as depsite having the Tablet off and clicking on the file names, and pointing it where to save. Nothing appears to happen, no data transfers...?? :(
Are you sure you're doing everything correctly? When the tablet is off and you connect it to the PC via USB, Windows should play the "USB device connected" sound effect, quickly followed by the "USB device disconnected" sound effect. Take a look at the Windows device manager - the Preloader VCOM device should appear there for this brief period, and it must not have a warning triangle (that would be a sign of missing drivers).

Do you think I'll be able to get those files if I root the device, and use a Root File Manager???
Yes, that should work, BUT I would not advise it. Looking at the update file, I saw it uses the newer block-based format. That means if you change the system partition in any minor way, e.g. by installing root / su binaries there, future updates will fail! Therefore, you shouldn't do anything that could modify the system partition (installing root, or even running TWRP), until you have a backup of the original state.

Also, without any official firmware from Lenovo yet... If I root it, will I be able to unroot it by just doing a simple "Factory Reset" within Android OS, or does this keep the root do you know?? Never really used Factory Reset, as always wipe the device in a custom recovery....
No, a factory reset will not unroot! Root is either installed on the system partition (the old way), which Android considers read-only, or it is installed in a modified boot.img (the new way), which also won't be touched by Android. A factory reset, regardless whether performed by Android or a custom recovery, just wipes the data and cache partitions.
 
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Lister Of Smeg

Senior Member
May 20, 2013
698
232
That sounds quite unlikely to me. Have you tried what I wrote before? Start holding the volume up button before you turn on the tablet. Then press the power button to turn it on, release the power button again, but keep holding volume up all the time.

Yes, I tried that... no matter what order/process I take. It each ends up in the same result. I did the holding of the Vol Up, then pressing Power (waited it for it to Vibrate, before letting go of Power... as instructed by Lenovo tech Support) and still would not get past the white screen, with Lenovo logo. :(

That's not an error, that is in fact the stock recovery! The menu is missing, but that's normal for some devices. There's a "secret" key combination you need to press to activate the menu. Try power+volume up again (or to be more specific, hold down the power button, then "click" the volume up button, then release the power button; do not hold down the power button for 10 seconds or longer, that'll probably reboot the tablet).

I thought that was recovery, as I've seen the ill looking Android collapse on other Android devices when a flash has failed, but normally I see more of a menu... Like to Apply Update (I guess official internal OS updats). I shall try that trick in a second, to see if I can get the menu to appear. May have to do it at home, as I know ADB app sends our works AV to thinking its a virus, when it's safe... lol


Are you sure you're doing everything correctly? When the tablet is off and you connect it to the PC via USB, Windows should play the "USB device connected" sound effect, quickly followed by the "USB device disconnected" sound effect. Take a look at the Windows device manager - the Preloader VCOM device should appear there for this brief period, and it must not have a warning triangle (that would be a sign of missing drivers).

The drivers installed correctly here (work, running Windows 10 x64), all went smoothly. When I plugged the Tablet in, it came up saying something about PreLoader driver... However at home, the drivers failed... But that could be my old screwy build of Windows 7x x64.... So gonna try again at work for that part.


Yes, that should work, BUT I would not advise it. Looking at the update file, I saw it uses the newer block-based format. That means if you change the system partition in any minor way, e.g. by installing root / su binaries there, future updates will fail! Therefore, you shouldn't do anything that could modify the system partition (installing root, or even running TWRP), until you have a backup of the original state.

Oh great, terrific... :( So I gotta be extra careful then!! lol. No rooting or mods until at least I can pull this ReadBack backup off... Oh I do love my Xposed!! :D

So once I've got my first official ReadBack backup, with no mods or alterations. Then I'm safe to do whatever...??
Providing I've got my first ReadBack before I do anything, if we are able to get TWRP into the Recovery Partition of the Tablet. Will this TWRP Recovery affect /System and OTA updates?? or is that only the Recovery partition affected, and System will stay intact??

Also, once (or, IF) I have TWRP, could I do a full system backup there. Prior to any mods, and can fully restore to stock (with the addition of TWRP recovery and not Stock) via the TWRP Recovery then... As wonna get an as close to stock backup as poss in TWRP. And then a fully setup with all the Apps, Mods, Tweaks and root Apps setup and then back that up. I assume I can always restore to the first TWRP backup without root at a later.

/ If any of that ^ makes sense? lol


No, a factory reset will not unroot! Root is either installed on the system partition (the old way), which Android considers read-only, or it is installed in a modified boot.img (the new way), which also won't be touched by Android. A factory reset, regardless whether performed by Android or a custom recovery, just wipes the data and cache partitions.

Fair enough, I kinda assumed that a Factory Reset within the Android OS will keep the root, and only wipe user added data, such as Apps, Pictures, Music, Files... and anything added to the /System would be left behind. My old devices (N7000 and i9100) only use the old way at the moment for rooting, as in writing to the system partition. When trying to use the new Boot.img way (as in Systemless root) causes both devices to crash, as they don't have the pre-modded Boot.img yet.

But assuming if I made a previous backup of the whole Tablet in TWRP before rooting (or do I need root, to push TWRP). Then go onto root the Tablet afterwards, if I then restore the Tablet to the first pre-root backup in TWRP will over write the root files back to stock??

/ sorry for all the questions, and what-if's.... ? ;) I understand Android, and fully know my Samsung models inside out... Just not sure when it comes to Lenovo, as it seems to use a different structure, and partition layout. And at moment, till I get my head around it, seem as stable/fool-proof in not making non-changeable choices, that can be corrected at a later date. Just it's my dads Tablet, and don't want to mess anything up as yet... As I'll prolly have to buy it off him ;) lol

Anyway, thanks for your continued help on this.... I'll let you know how I get on... :)

Cheers, Lister
 

Tzul

Senior Member
Jun 25, 2014
421
430
The drivers installed correctly here (work, running Windows 10 x64), all went smoothly. When I plugged the Tablet in, it came up saying something about PreLoader driver... However at home, the drivers failed... But that could be my old screwy build of Windows 7x x64.... So gonna try again at work for that part.
The driver I linked can be installed with a simple right-click in Windows 8 and later. But in Windows 7, the installation procedure is more involved, as described in the included readme.


Oh great, terrific... :( So I gotta be extra careful then!! lol. No rooting or mods until at least I can pull this ReadBack backup off... Oh I do love my Xposed!! :D
So once I've got my first official ReadBack backup, with no mods or alterations. Then I'm safe to do whatever...??
Yes, if you get the SPFT to work with your tablet, you can make a backup and restore it anytime you want.

Providing I've got my first ReadBack before I do anything, if we are able to get TWRP into the Recovery Partition of the Tablet. Will this TWRP Recovery affect /System and OTA updates?? or is that only the Recovery partition affected, and System will stay intact??
The first time you run TWRP, it asks you whether or not you'd like to allow changes to the system partition. If you choose yes, TWRP will rename a certain system file on exit, and will also offer to install a SuperSU stub for root. You see, Android has a mechanism that restores the stock recovery on every Android boot! Therefore, TWRP will be automatically replaced by the stock recovery again, unless you allow TWRP to rename that file, or install SuperSU. Both these things will intentionally break that Android restore mechanism.
On your tablet, you should probably forbid TWRP to make those changes. But even if you do, other things in TWRP can still change the system partition regardless. Installing the zip files for Xposed or SuperSU, for example. Or even restoring a TWRP backup of the system partition (because they are file based, but a block-based update doesn't just care about the file contents, but also about where exactly the files are located on the partition/disk, which will change with a file-based restore).

That's why "systemless" Root and Xposed are a thing these days. They don't install the files to the system partition anymore like they used to, but somewhere else (the ramdisk of the boot image, as far as I know), and use some trickery to make the files appear in the filesystem where they are expected.

Concerning OTA updates: they will fail if the system partition was modified. So if you want to install one, you either have to roll back to an unmodified system and stock recovery, then install the update, then install root, Xposed, etc. again (tedious). Or you can modify the updater-script inside the update, and make it work with modified systems, then install the adjusted update with TWRP. But that requires know-how and will only work with the old file-based updates, not the new block-based ones.

Also, once (or, IF) I have TWRP, could I do a full system backup there.
No. As just mentioned, TWRP backs up the files (their content), which is not enough for block level accuracy. You need a system image backup. Which can also be made with TWRP, if it has been configured properly.

But assuming if I made a previous backup of the whole Tablet in TWRP before rooting (or do I need root, to push TWRP). Then go onto root the Tablet afterwards, if I then restore the Tablet to the first pre-root backup in TWRP will over write the root files back to stock??
Yes, but again, you need to backup and restore the system image (the entire partition, including "empty" space, not just the files as TWRP normally does).

/ sorry for all the questions, and what-if's.... ? ;) I understand Android, and fully know my Samsung models inside out... Just not sure when it comes to Lenovo, as it seems to use a different structure, and partition layout. And at moment, till I get my head around it, seem as stable/fool-proof in not making non-changeable choices, that can be corrected at a later date. Just it's my dads Tablet, and don't want to mess anything up as yet... As I'll prolly have to buy it off him ;) lol
It has nothing to do with Samsung vs. Lenovo. It's about the chipset - MediaTek in your case. A Lenovo device with a Qualcomm chip, for example, will have a different partition layout and obviously won't work with the SPFT. And most of the things I just talked about (file-based vs. block-based updates, the "sanctity" of the system partition, etc.) are general Android things and not specific to the chipset.
 
Last edited:

Lister Of Smeg

Senior Member
May 20, 2013
698
232
Hi @Tzul,

Ok, slowly making progress here... Yippie!! :D lol

Still can't enter recovery via hardware buttons... No matter how many times I try, and in whatever order and timing. I even tried holding Power & Vol Up, then when it FREEZES on white screen with Lenovo logo. Then tried releasing Vol Up also, and then holding it down again... like how to reveal 'Secret Menu'. But still nothing appears for recovery!! :(

However, that said... I am now able to enter Recovery... via using ADB Fastboot Recovery, then using those key combo commands to reveal the secret menu. Which that all now works, and get a full list of options to choose from there... :D So thank you for that!! :D

I've had another go at trying to install PreLoader driver again on my home PC (Win7 x64) and it now appears to do something, more than previously done... But errors, and still does not pull those files. Maybe you might be able to see where going wrong via the screenshot??

vqtl6b.jpg


Yes, if you get the SPFT to work with your tablet, you can make a backup and restore it anytime you want.
Once I get this App working, and working reliably... I think I'd feel a lot more comfortable and happier, knowing I have a decent back up to rely on. Just this App is new to me, and at moment (with difficulties of entering Recovery and getting this App to work). Where as comparison to Odin. Just have to put phone into Download Mode, add the Firmware File... and thats it. By the looks of things, this App is very very similar. Just with its hit/miss at moment, till I've ironed out why its not working... Just want to know I have STOCK rom to return too, in aid of firmware updates.

Concerning OTA updates: they will fail if the system partition was modified. So if you want to install one, you either have to roll back to an unmodified system and stock recovery, then install the update, then install root, Xposed, etc. again (tedious). Or you can modify the updater-script inside the update, and make it work with modified systems, then install the adjusted update with TWRP. But that requires know-how and will only work with the old file-based updates, not the new block-based ones.
I've seen TWRP (more specifically, TWRP 3.x) mention about allowing System modifications with my Samsung device. I think in the past, I've answered both ways... Allow / Do Not Allow when switching Roms every so often.

So basically it's a toss up of whats more important...? Receiving OTA updates, or running Root on the device. As long as I can get this first initial ReadBack backup, then should be happy either way... As can always restore back to fully STOCK, run the update, then flash TWRP and Root apps again??

No. As just mentioned, TWRP backs up the files (their content), which is not enough for block level accuracy. You need a system image backup. Which can also be made with TWRP, if it has been configured properly.
Will have a look on my current Samsung / TWRP about making full system based images. But that said, I still won't receive OTA updates restoring back to this way, as already modified the device/OS with TWRP... preventing this. But could be quicker/easier way to return to STOCK (minus updates). And this would be safe to do, based on the BLOCK BASED partition on this device? (Only ever been used to FILE BASED twrp backups).

It has nothing to do with Samsung vs. Lenovo. It's about the chipset - MediaTek in your case. A Lenovo device with a Qualcomm chip, for example, will have a different partition layout and obviously won't work with the SPFT. And most of the things I just talked about (file-based vs. block-based updates, the "sanctity" of the system partition, etc.) are general Android things and not specific to the chipset.
Yeah I hear you on Samsung vs Lenovo, being Exynos vs MediaTek... What I mean't, is I'm just more used too and comfortable with the way things work on Samsung. I know (so far... lol) that I can never really brick my Samsung devices (other than the leaked ICS kernel) as I can restore fully with STOCK rom in Odin. And that all my devices (Samsung, HP Touchpad, ZTE Blade) all use partitions one way or another... as it was a curve to learn Samsung shares Recovery with its Kernel and vice versa... Where as the Blade, they were both separated... I'll get there slowly with MediaTek devices... ;) lol... But most of all, I thank you, for all your time, patience and support guiding me along this way... MUCH APPRECIATED!!! :D

Edit: I am amazed that Lenovo don't have anything public on their website regarding firmware, to allow customers to restore themselves. I've downloaded their "Lenovo Smart Assistant" App which is supposed to support phones and Tablets. But does not detect mine, either alive or dead mode. When searching for it within the App, nothing shows for it either... Or the Tab2 family either..?? May try another cheeky online chat support call to them again, see if they can release anything firmware wise ;) lol

Many thanks, Lister
 
Last edited:

Tzul

Senior Member
Jun 25, 2014
421
430
I've had another go at trying to install PreLoader driver again on my home PC (Win7 x64) and it now appears to do something, more than previously done... But errors, and still does not pull those files. Maybe you might be able to see where going wrong via the screenshot??
That's the same error the other person on the Lenovo forum had. I have a feeling that the driver isn't installed correctly. Have you looked at the Windows device manager, Ports (Com & LPT) section? Does a new device appear there after connecting the powered-off tablet, and does that device NOT have a warning triangle?

Maybe you could try the SPFT on a Windows 8 or 10 machine, where the signed driver can be installed with the simple right-click method. Otherwise, you could find an install an unsigned driver for Windows 7, and try again. Maybe this error is also caused by an incorrect scatter file, wrong download agent, or bug in the specific SPFT version. You could try an older version such as v5.1516. Here's someone who encountered the same error and "fixed" it by using this older version and a slower PC...

So basically it's a toss up of whats more important...? Receiving OTA updates, or running Root on the device. As long as I can get this first initial ReadBack backup, then should be happy either way... As can always restore back to fully STOCK, run the update, then flash TWRP and Root apps again??
Yes. You should probably go with systemless root on this tablet, but whether the system or boot image get modified, an OTA update will fail either way if it does integrity checks. So there's no way around making backups of the untouched partitions and restoring them when necessary.

Will have a look on my current Samsung / TWRP about making full system based images. But that said, I still won't receive OTA updates restoring back to this way, as already modified the device/OS with TWRP... preventing this. But could be quicker/easier way to return to STOCK (minus updates). And this would be safe to do, based on the BLOCK BASED partition on this device? (Only ever been used to FILE BASED twrp backups).
That option might or might not exist in your Samsung's TWRP. Usually, newer TWRPs are configured to have a "System Image" entry in the Install -> Install Image partition list, so that it is possible to flash a system.img file easily from within TWRP. This same "System Image" entry can also be made visible in the Backup/Restore partition list, but normally it isn't.

I am amazed that Lenovo don't have anything public on their website regarding firmware, to allow customers to restore themselves. I've downloaded their "Lenovo Smart Assistant" App which is supposed to support phones and Tablets. But does not detect mine, either alive or dead mode. When searching for it within the App, nothing shows for it either... Or the Tab2 family either..?? May try another cheeky online chat support call to them again, see if they can release anything firmware wise ;) lol

Many thanks, Lister
Well, you're not supposed to mess with these devices. Only a fraction of users install root or Xposed anyway. I've never tried the "Lenovo Smart Assistant", so I can't say anything about that.
Anyway, you're welcome. :)
 

Lister Of Smeg

Senior Member
May 20, 2013
698
232
Hi @Tzul,

Still not having any luck with this... :( Boo-hoo.... As below, is what happened and what I've tried..

That's the same error the other person on the Lenovo forum had. I have a feeling that the driver isn't installed correctly. Have you looked at the Windows device manager, Ports (Com & LPT) section? Does a new device appear there after connecting the powered-off tablet, and does that device NOT have a warning triangle?

Maybe you could try the SPFT on a Windows 8 or 10 machine, where the signed driver can be installed with the simple right-click method. Otherwise, you could find an install an unsigned driver for Windows 7, and try again. Maybe this error is also caused by an incorrect scatter file, wrong download agent, or bug in the specific SPFT version. You could try an older version such as v5.1516. Here's someone who encountered the same error and "fixed" it by using this older version and a slower PC...

Installed at home, old dual core computer running Windows 7 x64. Installed driver as per instructions (Installed to Com18 port). On first install, it shows a new device with yellow explanation mark. So I delete the device, but keep the driver software files installed. Same error...

At work, Quad Core i5 running Windows 10 x64. Installed the driver using Right Click / Install option... Driver installs fine, no errors (Installed to Com15 port). Same error.

Tried with the very latest version of SPFT, and with the other older version as quoted on that website. At first the older one wouldnt show the partition on ReadBack mode, even with the ScatterFile=true remark at the end. So I just copied contents out of one of the other option.ini files and then it did. But still no joy. Tried various versions of SPFT (not all of them, will do some more tonight). Tried different USB cables, including the original official one at of the box.

Only thing not tried, finding a really really old computer...

Yes. You should probably go with systemless root on this tablet, but whether the system or boot image get modified, an OTA update will fail either way if it does integrity checks. So there's no way around making backups of the untouched partitions and restoring them when necessary.

I'm assuming there will never be a Systemless root for this device. As that requires someone to mod the Boot.img. And other than your good self, not seen anyone else offer support (or even use) this device, and I can't expect you to do that. Not to mention, can't even get the files off or access a firmware file for it.

I was hoping if I could get a STOCK firmware of backup of this device. Then if there was news of an update coming out. I could reflash back to STOCK, loosing all my mods and changes. Just to get the update, then attempt to re-root and tweak again... Gonna be a cat-n-mouse game me thinks... :( If I can ever get this backup to work in the first place...?? lol

That option might or might not exist in your Samsung's TWRP. Usually, newer TWRPs are configured to have a "System Image" entry in the Install -> Install Image partition list, so that it is possible to flash a system.img file easily from within TWRP. This same "System Image" entry can also be made visible in the Backup/Restore partition list, but normally it isn't.

Didnt get chance to check TWRP last night on Samsung devices, by time I went to bed... was too knackered and straight asleep... lol. Will check tonight... ;)

Well, you're not supposed to mess with these devices. Only a fraction of users install root or Xposed anyway. I've never tried the "Lenovo Smart Assistant", so I can't say anything about that.
Anyway, you're welcome. :)

No, it appears your not... I tried to speak to Lenovo again today... (sob story... Need to access a backup firmware in case Tablet dies under dads use, which is not too far from the truth...) However he was under the impression I could restore fully to STOCK if I access the Recovery (which I told him only works via ADB commands. He suggested again I should take it back to shop and get it replaced).

Anyway, I said... So does that mean the Lenovo Tablet has a hidden recovery image / rom / partition. And that if I was to "root the device, in order to make some Apps/Tweaks work" I could enter Recovery, and run the recovery option in the hidden menu and restore Tablet back to STOCK.

To which sadly I had to go back to work, and told him this. I said if he could leave me the reply, I'd check when back. Which he then said, "If the Tablet is rooted, it will then delete the recovery partition, meaning no recovery would be possible" which to me sounds a little far fetched... that rooting will actually DELETE a hidden recovery image/partition???

I'm sadly starting to think, have I picked the wrong device for my dad?? Same as with all mine, and what I did for my mums... I was able to install custom recovery easily. Especially in the case of my mum's Tesco's Hudl, I set it all up with STOCK rom (as there are no custom roms), however there is custom recovery which I flashed, rooted, and installed all rooted Apps. However, I have since been able to reflash it back to fully STOCK without any Root, and able to go back and fourth as often as like without fear of bricking, or potentially damaging any future updates/recovery....


Gonna try a few more times to get this to recognise and accept SPFT backing/restoring... Otherwise next week, I may consider taking back to the shops. Pity, as the Tablet itself is seems really nice so far (even though barely used it yet). But just worried cannot make backup images, or can easily break Updates/Stock Restoring.... :(

Cheers, Lister
 

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  • 4
    IT WORKS

    Hey guys, It's me again. I managed to crack down the russian CAPTCHA and downloaded those files, and it just WORKS! I now have full root on my TB3-850f. I wrote down simple HOW-TO:
    1) Copy SuperSU-v2.79-SR1-20161221223537.zip to the tablet
    2) Enable developer and USB debugging
    3) Open cmd in folder with ADB and FASTBOOT
    4) Type these commands:
    - adb reboot bootloader
    - fastboot oem unlock
    5) Hold down power button and reboot. Repeat 2) and enable OEM UNLOCK
    6) Repeat 3) and type: adb reboot bootloader
    7) then type: fastboot boot recovery.img
    (must be copied in the same folder as adb.exe and fastboot.exe)
    8) Use TWRP to install SU
    Now you have ROOT :)
    I also uploaded the files here: filedropper.com/tb3850froot
    3
    How to backup/unbrick TB3-850F

    Hi guys,
    I'm the dude who bricked his tablet from Lenovo Forums... Tzul tried to help me but with no luck.
    Yesterday I managed to fully backup that bricked tablet and even unbricked it using some russian ROM for TB3-850M. I think the problem was in the driver or Scatter file (or both). Just use the SPFlashTools, driver and scatter from the russian ROM. Oh and use download agent DA_SWSEC . Here is the link:
    well apparently I am not authorised to post links here, so google TB3-850M_S100029_160924_ROW on russian site novo-forums

    Anyway, I still need to root it, so if I can help somehow (share the backup or somenthing) just let me know. Thanks
    3
    hi,
    So with these files, have you been able to take a FULL BACKUP of of the TB3-850F model (even though thats for the TB3-850M) model...? And then restored it back to the device ok, with no problems....???
    Yes I was able to do full backup, but I only flashed boot and recovery partition from TB3-850M firmware, because I suspected one of them to be corrupted in my tablet (it was bricked). It worked well so I didn't try to flash any other partitions - I didn't want take the risk.
    I'm really looking forward to root this tablet, and I'm glad I could cotribute(a little) to the process of getting a root :)
    Here is my backup: ufile.io/5f0bb
    If you need anything else, just write in this thread and I will try to help.
    2
    I think the problem was in the driver or Scatter file (or both). Just use the SPFlashTools, driver and scatter from the russian ROM. Oh and use download agent DA_SWSEC .

    I've downloaded and tested this, and yes, it works. I've checked different combinations, and the problem is in fact the DA. Also Tzul's scatter file doesn't quite fit this tablet. The scatter file in the russion ROM fits and this should be used (but that's not the reason for the error given by SPFT).

    I could make a full backup and verify that the images are OK (system.img can be mounted, "file boot" and "file recovery" say "Android bootimg").

    Key combo for recovery mode
    I had the same problem as Lister: power and vol- gets you in that chinese test menu and when you hold all 3 buttons it doesn't boot. This is how you do it:
    • press and hold power
    • wait 1 second
    • press and hold vol+ and vol-
    • when it vibrates, relase all buttons
    Once you get the timing, you can do it consistently.

    harry
    2
    It actually fits without problem and is almost identical.
    Yes, sorry, I got confused about which scatter file you guys where talking about and compared with the one you made for the Tab2. The one for the Tab3 is indeed the same.

    I'm really looking forward to root this tablet
    I am looking into building TWRP for this tablet. But I'm a complete noob when it comes to building Android, so it could take some time and I make no promises.
    @Tzul: Can you suggest a device tree I can use as a starting point for this?