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[ROM][6.0][STOCK]{UPDATED} Lenovo Tab 3 8"/TB3-850F

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MotoJunkie01

Senior Member
Apr 2, 2016
2,403
1,213
Corbin
STOCK ANDROID 6.0 MARSHMALLOW ROM
FOR THE LENOVO TAB 3 8"/TB3-850F
TWRP FLASHABLE ZIP
FORCE ENCRYPTION & DM-VERITY DISABLED

DISCLAIMER: Your warranty will be voided by installing this ROM, unlocking your bootloader, or flashing a custom recovery. You hereby assume sole responsibility for any positive or negative consequences incurred by flashing this ROM. As always, flashing your Android device or otherwise altering its file system & partitions involves an inherent risk. I am not responsible for any devices which are bricked or otherwise rendered inoperable as a result of flashing this ROM. However, in such scenarios,
I will provide all support feasibly possible. Follow the simple instructions carefully and you should experience no adverse affects.
Lenovo's open source code for this ROM encompasses both the 850F & 850M variants of this tablet. Therefore, this ROM should be completely compatible with the TB3-850M as well.


NOTES:

This Stock Android 6.0 ROM is virtually unmodified. However, it should be noted that dm-verity (device mapping) and force encryption have been disabled via patched boot image. This is the most current stock OS for the Lenovo Tab 3 8"; therefore, no OTAs will need to be installed subsequent to flashing this ROM. In order to ensure that force encryption gets disabled, it is imperative that the /userdata (Data) partition is formatted in TWRP prior to Installation. Please carefully follow the below instructions.
For those members who want a pure stock experience, but also want root access of the stock OS, I'm currently compiling a deodexed & zipaligned version of this ROM, fully rooted with Magisk 14.0 & BusyBox binaries pre-installed.

SPECIFICATIONS:

Android Version: 6.0 Marshmallow
Build No: TB3-850F_S100031_171010_ROW
Kernel Version: 3.18.19
SDK Version: 23
Software Version: TB3-850F_160412
Build ID: MRA58K
Android Security Patch Level: 9/05/2017
Runtime Version: ART 2.1.0
Hardware Version: LenovoPad TB3-850F
Board Platform: MediaTek MT6735M
CPU: 64-Bit, Quad-Core Cortex A-53 - 1.0GHz
GPU: Mali T720 - 450MHz
RAM: 1GB
OS Build Date: 10/10/2017


Source Code: http://pcsupport.lenovo.com/us/en/products/tablets/a-series/tab3-8/downloads/ds112711


REQUIREMENTS:

1. Unlocked bootloader;
2. TWRP recovery;

This is a pure stock, unmodified, TWRP flashable Android 6.0 Marshmallow ROM for the Lenovo Tab 3 8". This ROM was compiled from the most recent stock /boot and /system images. However, as noted previously, the boot image has been unpacked, patched, and repacked in order to disable dm-verity and force encryption. Because raw firmware images were used in compiling this ROM, the file size is in excess of 1GB (approximately 1.35GB).

INSTRUCTIONS:

1. Download the ROM from the link provided and save it to your external micro SD card. Do not save to internal storage, as your /data partition will need to be formatted prior to installation;
2. Boot your tablet into TWRP recovery;
3. Wipe /system, /data, /cache & /Dalvik-ART cache. Also, select "Wipe", then "Format Data." This step is crucial to ensure disabling of force encryption. Please note that once installed, you may go to SETTINGS>>SECURITY and opt to encrypt the userdata on the tablet;
4. Select INSTALL, navigate to the location in which you saved the ROM zip file, and initiate installation. Flashing will complete in approximately 3 - 4 minutes;
5. Reboot system.

You should now have unmodified stock Android 6.0 installed on your Tab 3, as well as disabled dm-verity and disabled force encryption.

DOWNLOAD LINKS:

Stock Android 6.0 ROM --
TB3-850F_S100031_171010_ROW: https://drive.google.com/file/d/1iMf0Ns_XWGpYlNmXCvUsW_1DfaRMeIuO/view?usp=drivesdk

Stock Recovery Image: https://drive.google.com/file/d/1D6A7b080luzsSf0xLJSCqPBNeQLSWo94/view?usp=drivesdk

Unpatched Stock Boot Image: https://drive.google.com/file/d/1azgIrPbfJHBzZF9R4IUMxIGNga6vjipD/view?usp=drivesdk

Lenovo File Manager (APK): https://forum.xda-developers.com/android/general/app-lenovo-file-manager-lenovo-tab-3-8-t3706161

Lenovo Tab 3 8" User Guide --
TB3-850F & TB3-850M (English)(PDF): https://drive.google.com/file/d/18gCTfuZecJnlB0ddBIN02YPaDpuvmzov/view?usp=drivesdk

Older Build(s):
TB3-850F_S100030_161209_ROW: https://drive.google.com/file/d/0B1Sfod4HWfk2aTNtVmJHZGpWZEE/view?usp=drivesdk


BUGS: Please report any and all bugs, no matter how seemingly trivial or insignificant. For those members with the knowledge, please submit a proper bug report. If you are not sure how, simply provide as many facts & details as possible. If you are having problems with apps, please specify as to whether the app is from Google Play. Also, please DO NOT submit bug reports unless you are utilizing this ROM in its present form -- unmodified, pure stock. Custom kernels, mods & tweaks (e.g. Xposed framework) & any deviations from pure stock will make it futile to analyze bug reports. Instead, provide with detail the precise nature of the problem. If reporting a bug, please specify if you are rooted (systemless or system-mode) and/or have BusyBox binaries installed. Submit screenshots of bugs if possible.
 
Last edited:

MotoJunkie01

Senior Member
Apr 2, 2016
2,403
1,213
Corbin
My custom ROM for this tablet should be coming out of the Android Kitchen later this evening. I've dubbed it Ethereal OS v1.1 [Android 6.0.1]. Extremely lightweight yet moderately feature packed.
 
My custom ROM for this tablet should be coming out of the Android Kitchen later this evening. I've dubbed it Ethereal OS v1.1 [Android 6.0.1]. Extremely lightweight yet moderately feature packed.

Nice!

After flashing the stock zip TWRP says unknown error. It booted up fine to where you login to your gmail and "bluetooth sharing has stopped working" pops up. Bluetooth can not be turned on within settings. I can not double swipe down to get to the notifications and the "Home" and "Recents" buttons do not seem to work although they both vibrate when pressed.

I will flash stock with SPFT and try your stock rom again.
 

MotoJunkie01

Senior Member
Apr 2, 2016
2,403
1,213
Corbin
Nice!

After flashing the stock zip TWRP says unknown error. It booted up fine to where you login to your gmail and "bluetooth sharing has stopped working" pops up. Bluetooth can not be turned on within settings. I can not double swipe down to get to the notifications and the "Home" and "Recents" buttons do not seem to work although they both vibrate when pressed.

I will flash stock with SPFT and try your stock rom again.
I got the same error with Bluetooth Share force closing two times at the setup screen. Probably a corruption issue during archiving the ROM. I'll do an md5 and archive the ROM again.
 

rongallant

New member
Jun 8, 2017
3
0
Seemed to work, however the loading images and screen is still lenovo. Also they lenovo apps are still there.
 

rongallant

New member
Jun 8, 2017
3
0
This is not a custom ROM. This is pure stock. The Lenovo boot logo, boot animation & apps are supposed to be there. Like the title implies this an "Unmodified" stock ROM.

My bad, understood.
On another note, I am finding it very buggy. The home and overview buttons do not work. They show you clicked it along with the haptic feedback, but nothing happens. The back button works and is the only way I know to get back to the home screen.
Also the tool panel you pull from the top stops working after a little while until I reboot. Then works for a little while.
The Play store downloads barely work. They show pending and nothing happens. I force quite, cleared the cache, disabled, reverted to the stock app and it works for a little bit. Then the other Play Store app comes back. Anyways, I am not complaining. I appreciate the work you put into this. It's awesome we get to do it at all. Just giving my feedback. P.S. It's a new TB3-850F.
 

MotoJunkie01

Senior Member
Apr 2, 2016
2,403
1,213
Corbin
My bad, understood.
On another note, I am finding it very buggy. The home and overview buttons do not work. They show you clicked it along with the haptic feedback, but nothing happens. The back button works and is the only way I know to get back to the home screen.
Also the tool panel you pull from the top stops working after a little while until I reboot. Then works for a little while.
The Play store downloads barely work. They show pending and nothing happens. I force quite, cleared the cache, disabled, reverted to the stock app and it works for a little bit. Then the other Play Store app comes back. Anyways, I am not complaining. I appreciate the work you put into this. It's awesome we get to do it at all. Just giving my feedback. P.S. It's a new TB3-850F.
Yes. Very buggy indeed. I have determined that the bugs are due to corruption during the unpacking of the system image. I'm repacking the ROM now to alleviate the bugs. Thanks for your input...
 
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MotoJunkie01

Senior Member
Apr 2, 2016
2,403
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Corbin
I've managed to fix the major bugs reported upon initial install of the ROM -- Recents & Home Buttons, Quick Pulldown Menu, Google Framework bugs, New App Shortcut bugs, etc. Simply corruption during packing (archiving) the ROM zip. I will try my best to get a new build posted sometime today.
 

D-Assault

New member
Jun 12, 2017
3
0
I've managed to fix the major bugs reported upon initial install of the ROM -- Recents & Home Buttons, Quick Pulldown Menu, Google Framework bugs, New App Shortcut bugs, etc. Simply corruption during packing (archiving) the ROM zip. I will try my best to get a new build posted sometime today.

Dear MotoJunkie

İs it possible to upload stock Fm Radio Aplication(offline radio) of Tab3 8? İn my Turkish model, theres no Fm radio aplication. I need it to use tablet in my car.
Thanks
 

rongallant

New member
Jun 8, 2017
3
0
I've managed to fix the major bugs reported upon initial install of the ROM -- Recents & Home Buttons, Quick Pulldown Menu, Google Framework bugs, New App Shortcut bugs, etc. Simply corruption during packing (archiving) the ROM zip. I will try my best to get a new build posted sometime today.


Did you get around to uploading it? I am unable to use the OTA update file. Says its missing 'android-info.txt'


Also, anyone care to point me to a way to get back to stock/unrooted?? Nooooo, I didn't backup my ROM first. That would have made way to much sense.
 

MotoJunkie01

Senior Member
Apr 2, 2016
2,403
1,213
Corbin
I've been out of commission, unfortunately, due to impending health issues once again. I know that hospital food sucks, that the pretty nurses don't typically put out easy, and that the hospital WiFi restrictions can easily be bypassed with a proxy server address. Lol. And that's all I've learned in the past ten days. Anyway, hope to be back in my daily routine in the next day or so and finishing some stuff up for this device.
 

spiker_80

New member
Jul 6, 2017
1
0
Hi, is this thread alive? I'm interested in solution because i have about 60 tablets and need a solution to clone form one source tablet (config, apps, wlan, users, etc.) to other 59. I have tried adb backup --twrp and it went ok, but when i tried restore it gave errors with system partition and now i can only recover tablet with factory ROM from this thread (but it is buggy and cannot put it int to production like this). Is it possible to create system rom from other working tablet? Iwill be very pleased If You can write step by step, how to create zipped rom from working device so i can then upload it to share with others.
 

MotoJunkie01

Senior Member
Apr 2, 2016
2,403
1,213
Corbin
Hi, is this thread alive? I'm interested in solution because i have about 60 tablets and need a solution to clone form one source tablet (config, apps, wlan, users, etc.) to other 59. I have tried adb backup --twrp and it went ok, but when i tried restore it gave errors with system partition and now i can only recover tablet with factory ROM from this thread (but it is buggy and cannot put it int to production like this). Is it possible to create system rom from other working tablet? Iwill be very pleased If You can write step by step, how to create zipped rom from working device so i can then upload it to share with others.
The thread is alive and I'm currently ironing out the errors on the posted ROM. The errors are due to a couple of permissions which are omitted on my updater-script file. I'll be posting an updated and hopefully error free release this week. Thanks for your interest and sorry for the delay in development. I've had a number of health issues of late and I'm now recovering.
 
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sailor1977

New member
Jul 11, 2017
2
0
Problem after wiping /system

Hi,

I´m new right here. I bought a new TB3-850F and wanted to flash the Original Stock Rom. After opening the Bootloader and booting into twrp like this way https://forum.xda-developers.com/android/general/guide-lenovo-tab3-8-tb3-850f-t3559786 I wiped the /data /System /dalvic and /Cache. After that I rebooted the system.

But it only shows after starting the Lenovo-Logo. No more booting. Because of this I can´t start the fastboot modus with Minimal ADB and Fastboot.

Is there some idea how I can boot into fastboot?

Many thanks for your help,

sailor1977
 

sailor1977

New member
Jul 11, 2017
2
0
Hi,

I´m new right here. I bought a new TB3-850F and wanted to flash the Original Stock Rom. After opening the Bootloader and booting into twrp like this way https://forum.xda-developers.com/android/general/guide-lenovo-tab3-8-tb3-850f-t3559786 I wiped the /data /System /dalvic and /Cache. After that I rebooted the system.

But it only shows after starting the Lenovo-Logo. No more booting. Because of this I can´t start the fastboot modus with Minimal ADB and Fastboot.

Is there some idea how I can boot into fastboot?

Many thanks for your help,

sailor1977


I´ve got a solution: After powering down, press power, wait 1 sec then hold both vol up & down also (all 3 Buttons) until vibrates. After starting in recovery Modus hold power button und press once the vol up.
With help of: https://forum.xda-developers.com/android/help/lenovo-tab3-8-2016-custom-recovery-t3483454 post #66
 

MotoJunkie01

Senior Member
Apr 2, 2016
2,403
1,213
Corbin
Ok. I've debugged the Stock 6.0 ROM in the OP. Fixed the Bluetooth force close issue at startup and the bugs involving the hardware buttons and the pull down menu. I'm traveling for work at the moment. Soon as I'm back home Monday I'll post the fixed build in the OP.
 
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MotoJunkie01

Senior Member
Apr 2, 2016
2,403
1,213
Corbin
@Hemphiz, I hope all is well my friend. Something I wanted to get your input on. It seems that a few members have been experiencing boot loops and other problems after following the TWRP & Root thread I revised. I'm sort of at a brick wall in terms of figuring out what's going on. I'm thinking that maybe there are regional variants that are incompatible with the TWRP we use. Or, it could be one of those situations where instructions are not being closely followed. What are your thoughts? Thanks.
 
Last edited:

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  • 4
    STOCK ANDROID 6.0 MARSHMALLOW ROM
    FOR THE LENOVO TAB 3 8"/TB3-850F
    TWRP FLASHABLE ZIP
    FORCE ENCRYPTION & DM-VERITY DISABLED

    DISCLAIMER: Your warranty will be voided by installing this ROM, unlocking your bootloader, or flashing a custom recovery. You hereby assume sole responsibility for any positive or negative consequences incurred by flashing this ROM. As always, flashing your Android device or otherwise altering its file system & partitions involves an inherent risk. I am not responsible for any devices which are bricked or otherwise rendered inoperable as a result of flashing this ROM. However, in such scenarios,
    I will provide all support feasibly possible. Follow the simple instructions carefully and you should experience no adverse affects.
    Lenovo's open source code for this ROM encompasses both the 850F & 850M variants of this tablet. Therefore, this ROM should be completely compatible with the TB3-850M as well.


    NOTES:

    This Stock Android 6.0 ROM is virtually unmodified. However, it should be noted that dm-verity (device mapping) and force encryption have been disabled via patched boot image. This is the most current stock OS for the Lenovo Tab 3 8"; therefore, no OTAs will need to be installed subsequent to flashing this ROM. In order to ensure that force encryption gets disabled, it is imperative that the /userdata (Data) partition is formatted in TWRP prior to Installation. Please carefully follow the below instructions.
    For those members who want a pure stock experience, but also want root access of the stock OS, I'm currently compiling a deodexed & zipaligned version of this ROM, fully rooted with Magisk 14.0 & BusyBox binaries pre-installed.

    SPECIFICATIONS:

    Android Version: 6.0 Marshmallow
    Build No: TB3-850F_S100031_171010_ROW
    Kernel Version: 3.18.19
    SDK Version: 23
    Software Version: TB3-850F_160412
    Build ID: MRA58K
    Android Security Patch Level: 9/05/2017
    Runtime Version: ART 2.1.0
    Hardware Version: LenovoPad TB3-850F
    Board Platform: MediaTek MT6735M
    CPU: 64-Bit, Quad-Core Cortex A-53 - 1.0GHz
    GPU: Mali T720 - 450MHz
    RAM: 1GB
    OS Build Date: 10/10/2017


    Source Code: http://pcsupport.lenovo.com/us/en/products/tablets/a-series/tab3-8/downloads/ds112711


    REQUIREMENTS:

    1. Unlocked bootloader;
    2. TWRP recovery;

    This is a pure stock, unmodified, TWRP flashable Android 6.0 Marshmallow ROM for the Lenovo Tab 3 8". This ROM was compiled from the most recent stock /boot and /system images. However, as noted previously, the boot image has been unpacked, patched, and repacked in order to disable dm-verity and force encryption. Because raw firmware images were used in compiling this ROM, the file size is in excess of 1GB (approximately 1.35GB).

    INSTRUCTIONS:

    1. Download the ROM from the link provided and save it to your external micro SD card. Do not save to internal storage, as your /data partition will need to be formatted prior to installation;
    2. Boot your tablet into TWRP recovery;
    3. Wipe /system, /data, /cache & /Dalvik-ART cache. Also, select "Wipe", then "Format Data." This step is crucial to ensure disabling of force encryption. Please note that once installed, you may go to SETTINGS>>SECURITY and opt to encrypt the userdata on the tablet;
    4. Select INSTALL, navigate to the location in which you saved the ROM zip file, and initiate installation. Flashing will complete in approximately 3 - 4 minutes;
    5. Reboot system.

    You should now have unmodified stock Android 6.0 installed on your Tab 3, as well as disabled dm-verity and disabled force encryption.

    DOWNLOAD LINKS:

    Stock Android 6.0 ROM --
    TB3-850F_S100031_171010_ROW: https://drive.google.com/file/d/1iMf0Ns_XWGpYlNmXCvUsW_1DfaRMeIuO/view?usp=drivesdk

    Stock Recovery Image: https://drive.google.com/file/d/1D6A7b080luzsSf0xLJSCqPBNeQLSWo94/view?usp=drivesdk

    Unpatched Stock Boot Image: https://drive.google.com/file/d/1azgIrPbfJHBzZF9R4IUMxIGNga6vjipD/view?usp=drivesdk

    Lenovo File Manager (APK): https://forum.xda-developers.com/android/general/app-lenovo-file-manager-lenovo-tab-3-8-t3706161

    Lenovo Tab 3 8" User Guide --
    TB3-850F & TB3-850M (English)(PDF): https://drive.google.com/file/d/18gCTfuZecJnlB0ddBIN02YPaDpuvmzov/view?usp=drivesdk

    Older Build(s):
    TB3-850F_S100030_161209_ROW: https://drive.google.com/file/d/0B1Sfod4HWfk2aTNtVmJHZGpWZEE/view?usp=drivesdk


    BUGS: Please report any and all bugs, no matter how seemingly trivial or insignificant. For those members with the knowledge, please submit a proper bug report. If you are not sure how, simply provide as many facts & details as possible. If you are having problems with apps, please specify as to whether the app is from Google Play. Also, please DO NOT submit bug reports unless you are utilizing this ROM in its present form -- unmodified, pure stock. Custom kernels, mods & tweaks (e.g. Xposed framework) & any deviations from pure stock will make it futile to analyze bug reports. Instead, provide with detail the precise nature of the problem. If reporting a bug, please specify if you are rooted (systemless or system-mode) and/or have BusyBox binaries installed. Submit screenshots of bugs if possible.
    2
    My custom ROM for this tablet should be coming out of the Android Kitchen later this evening. I've dubbed it Ethereal OS v1.1 [Android 6.0.1]. Extremely lightweight yet moderately feature packed.
    2
    Many thanks for clear summary!

    Couple of related questions:
    Re. disabled encryption:
    Will device / processes work faster with encryption disabled? And will this affect adoptive storage in any way?
    Re. dm-verity:
    Is there an option in this ROM to turn dm-verity on or off (as with force encryption)?
    Re pre-rooted ROM:
    Is there any advantage in supplying ROM pre-rooted? (Some OS customisers (eg OctOS) have dispensed with pre-rooted versions in order to give users greater flexibility.) I ask since I'd like to try Magisk on this device as I like some of its systemless modules, as well as ability to pass Safety net check.

    Incidentally, I just noticed Magisk Manager has Advanced Settings to Keep force encryption, and Keep dm-verity. Turns out (from Magisk XDA thread) that these are disabled by Magisk root by default, but can be toggled back on. Read that dm-verity may be needed for OTA updates. Read that leaving Keep force encryption disabled means that if encrypted data is removed (wiped), it won't be encrypted automatically on next boot.
    Might try Magisk on tablet soon to see if it does the same job, and report results. Works fine on my Huawei y550 phone with Lineage OS, and seems to be un-encrypted (shows option in Security to Encrypt Phone). Thanks, PW.
    My pre-rooted ROM for this device will actually be using Magisk 14.0 Systemless User Interface with full SafetyNet pass. Yes, correct; Magisk Manager does provide advanced options to allow dm-verity and force encryption to remain intact. I've personally never had the slightest use for dm-verity or force encryption. But, that's my personal opinion, and I'm sure there are users who would opt to use these features.
    Should Lenovo push any future OTA's for this tablet, I will update the stock ROM in this thread accordingly. My pre-rooted, deodexed ROM, which is presently nearing completion, will include Google's security patches up to August 1, 2017, as well as options to enable the Google Assistant.
    2
    After much battling with default force encryption and dm-verify on this tablet, I have finally decrypted this device and have compiled an otherwise unmodified Stock 6.0 ROM which is TWRP flashable. I have also updated this ROM to the most current version, which will alleviate any issues with installing OTAs. I will also be updating the stock Recovery Image to the latest version, TB3-850F_S100030_161209_ROW.
    2
    I've managed to fix the major bugs reported upon initial install of the ROM -- Recents & Home Buttons, Quick Pulldown Menu, Google Framework bugs, New App Shortcut bugs, etc. Simply corruption during packing (archiving) the ROM zip. I will try my best to get a new build posted sometime today.