[HOW-TO] Upgrade or Downgrade to any stock JB Firmware
- Thread starter pjc21
- Start date
fastboot -i 0x0B05 flash system blob
sending 'system' (800923 KB)...
FAILED (system read failed ( too many links ))
finished. total time: 0.002s
Not sure why it's failing, I have not seen this error before. Does fastboot see your device ok?
Maybe a bad/corrupt system blob? You could try and re-download and see if that works.
Late response, sorry. But I got it flashed finally, it just didn't like my front usb ports for some reason, now I'm stuck at boot screen, It's been booting for about 5-6 minutes, I'll give it 20 minutes.
No it will not restore your bootloader. Twrp cannot back up your bootloader. Boot partition refers to backing up the kernel partition I believe. But you should be able to downgrade then restore your twrp backup
Sent from my Nexus 7 using xda app-developers app
It does work
Great procedure! I did this with the US version. I thought I had trashed my tablet after installing a custom ROM. It would go as far as the ASUS boot screen and then lock up. So I downloaded the latest stock ROM and followed your steps. Worked flawlessly!
The only difference is I don't see my serial number when I do this. It doesn't seem to affect anything though because it does the burn without issue.
Thank you again for providing this.
Bob
Great procedure! I did this with the US version. I thought I had trashed my tablet after installing a custom ROM. It would go as far as the ASUS boot screen and then lock up. So I downloaded the latest stock ROM and followed your steps. Worked flawlessly!
The only difference is I don't see my serial number when I do this. It doesn't seem to affect anything though because it does the burn without issue.
Thank you again for providing this.
Bob
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look like you guys know the twrp better than me...
may I ask you some help, today I try to installa cyanogen 10.1 and (obviously) stack at the asus logo... at this point I restore only the boot of the stock version (4.2.1) trought twrp and now I have the cyanogen logo running but it doesen't start yet, did you try somthing like this?
may I ask you some help, today I try to installa cyanogen 10.1 and (obviously) stack at the asus logo... at this point I restore only the boot of the stock version (4.2.1) trought twrp and now I have the cyanogen logo running but it doesen't start yet, did you try somthing like this?
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No I have not tried to install CM 10.1 on the 4.2.1 bootloader but have read comments from others that have tried but looks like at the moment this is not possible.
In order to install CM 10.1 you'll have to downgrade to 4.1.1 (10.4.2.20).
I have tried installing CM10.1 on 4.2.1 and couldn't get it to work. I would just hang at the Asus screen.
Sent from my GT-I9300 using xda app-developers app
It worked after a little scare
I wouldn't recommend that. As mentioned in other posts, the filesystem changed.
My adventure:
I did the steps outlined in the OP. I was on 10.6.1.8. (I did a full wipe of everything, including internal storage)!
It was scary though, mine did get stuck. I waited 15 minutes after the blue bar had been filled! (So the total time passed was 26 minutes!) Then powered off, of course resulting in the FAILED below:
I do not know the reason for it to get stuck, but at least it didn't brick!
However, my pad rebooted, so I powered it into the boot-loader and surprise surprise there was a USB icon! From there I completed the steps and eventually my pad was a 10.4.2.20!
The fun didn't last very long though... It was late last night when finishing this downgrade and when setting up the system this morning I noticed some oddities.
My google account didn't fully connect, I regularly started to get a message stating "Refresh failed" and the play store either failed to connect completely or started to connect then fail.
I figured this had something to do with the never ending wait. I've tried a couple of different ROMs on the 10.4.2.20, but all seem to give the same issue. Flaky WiFi connection websites not loading and more of these issues.
I tried the procedure once more, but the effect ended up being the same (never ending writing, I waited about 20 mins after the blue bar had been filled!), I had to power it off and when finished with the rest of the procedure I had these connectivity issues again.
I ended up putting the 10.6.1.8 update on my MicroSD and updated through the usual update system. (Note that I DID redo the procedure without adding a recovery for the update to work. If you do add TWRP, the update will just reboot into TWRP, rather than processing the update).
Back on 10.6.1.8 everything works fine and dandy! (Albeit with building up lag as before.)
So, my conclusion is, certain models (mine is one of the newest black models, serial starting with D2, according to some sites manufactured 13/02/2013) might not be able to go back fully for whatever strange reason.
If there is anything I can do to help with this issue, please let me know.
I wouldn't recommend that. As mentioned in other posts, the filesystem changed.
My adventure:
I did the steps outlined in the OP. I was on 10.6.1.8. (I did a full wipe of everything, including internal storage)!
It was scary though, mine did get stuck. I waited 15 minutes after the blue bar had been filled! (So the total time passed was 26 minutes!) Then powered off, of course resulting in the FAILED below:
Code:
fastboot -i 0x0b05 flash system blob
erasing 'system'...
OKAY [ 0.384s]
sending 'system' (799748 KB)...
OKAY [142.182s]
writing 'system'...
FAILED (status read failed (Unknown error))
finished. total time: 1606.212sI do not know the reason for it to get stuck, but at least it didn't brick!
However, my pad rebooted, so I powered it into the boot-loader and surprise surprise there was a USB icon! From there I completed the steps and eventually my pad was a 10.4.2.20!
The fun didn't last very long though... It was late last night when finishing this downgrade and when setting up the system this morning I noticed some oddities.
My google account didn't fully connect, I regularly started to get a message stating "Refresh failed" and the play store either failed to connect completely or started to connect then fail.
I figured this had something to do with the never ending wait. I've tried a couple of different ROMs on the 10.4.2.20, but all seem to give the same issue. Flaky WiFi connection websites not loading and more of these issues.
I tried the procedure once more, but the effect ended up being the same (never ending writing, I waited about 20 mins after the blue bar had been filled!), I had to power it off and when finished with the rest of the procedure I had these connectivity issues again.
Code:
fastboot -i 0x0b05 flash system blob
erasing 'system'...
OKAY [ 0.349s]
sending 'system' (799748 KB)...
OKAY [139.567s]
writing 'system'...
FAILED (status read failed (Too many open files in system))
finished. total time: 1764.347sI ended up putting the 10.6.1.8 update on my MicroSD and updated through the usual update system. (Note that I DID redo the procedure without adding a recovery for the update to work. If you do add TWRP, the update will just reboot into TWRP, rather than processing the update).
Back on 10.6.1.8 everything works fine and dandy! (Albeit with building up lag as before.)
So, my conclusion is, certain models (mine is one of the newest black models, serial starting with D2, according to some sites manufactured 13/02/2013) might not be able to go back fully for whatever strange reason.
If there is anything I can do to help with this issue, please let me know.
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I have ADB setup, but I can't seem to get fastboot devices to work, but for some reason, when I reboot my device with fastboot using "fastboot -i 0x0b05 reboot" I can reboot the device, Am I doing something wrong?
---------- Post added at 05:13 PM ---------- Previous post was at 04:49 PM ----------
Which drivers are you guys using?
---------- Post added at 05:13 PM ---------- Previous post was at 04:49 PM ----------
Which drivers are you guys using?
Went to that Url you posted. Seems the way he downgraded was all done on the tablet and no need to connect to the PC?!
Sent from my ASUS Transformer Pad TF300T using xda app-developers app
I'm not sure what is going wrong, but I'm guessing you are in the wrong mode when issuing commands.
ADB commands can only be used when booted in Android's OS. Fastboot commands can only be used when in the fastboot mode of your device. (I tend to think of fastboot as my BIOS).
As mentioned in the first post the correct command is:
Code:
fastboot reboot-bootloaderYou can verify that you can actually communicate with the device (once in fastboot mode on your pad) by using:
Code:
fastboot devicesNote that the serial number mentioned with adb devices (while in Android) is the actual serial number of your device, in fastboot you do get a different hexadecimal code. (If you use TWRP to make a backup and check into its folders, you'll see TWRP/BACKUPS/<fastboot-serial>/<YourBackup>/... )
This is all documented in the very first post of this thread and works like a charm (provided you do have the USB drivers installed).
Use the search or the help topics to find out which drivers you can use in case yours don't work.
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Yes, that is indeed how it works if you do NOT have a recovery installed (I don't know about still being locked).
I tried and tested it. (Although I ended up with the same problems I mentioned before, the 10.4.2.20 kills my WiFi connectivity.)
What I had done...
I used the method in the first post here to get to stock 10.6.1.8 and did NOT add recovery and/or root at the end. So mine was really stock-stock and going into RCK mode gives the dead Android picture.
I copied the WW_epad-user-10.4.2.20.zip (from the downloaded Asus zip file) onto my microSD. Booted with it inside and got the system update notification in the notification area. I tapped it and got:
Next:
Then finally before the reboot:
The usual process of the official update happened (with the Android and star thingy first, then the blue bar updater) and finally booted into the setup wizard of 4.1.1.
Result:
I did this just to test the process and it worked for me. However, something in the 10.4.2.20 changes the way my WiFi works, because after using the WW_epad-user-10.6.1.8.zip to upgrade, the problems persist. I can only fix that by using the methods described in the first post here to get mine cleanly back on 10.6.1.8. Which makes me believe that mine was shipped with a different 10.4.2.20 or perhaps an intermediate version. I never checked the version before installing the OTA unfortunately...
Attachments
I'm actually in Fastboot mode but I don't see my device listed, I can tell the difference between adb and fastboot mode, I've been flashing with fastboot for a while now. I've actually flashed my TWRP without seeing my device listed using the fastboot devices command.
But I cant seem to flash the blob now.
I'm thinking its a drivers issue, I've used the drivers in Asus sync and universal naked drivers but no luck yet, maybe its windows?
PROBLEM SOLVED
You need to download the latest SDK
http://developer.android.com/sdk/index.html
the tools you need are in platform tools, you might wanna say that on the first post OP
Last edited:
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57After almost a full day of flashing I now have a 100% successful method of flashing any stock JB Firmware
With this method I have been able to successfully flash any stock JB Firmware from 10.4.2.9 all the way through to 10.6.1.27.5 without issue.
unfortunately you can not go back to ICS bootloader or firmware (there is a signature mismatch issue here).
Try this at your own risk, I will not be responsible for a bricked device.
Recommend doing NVFlash first so your tablet is Unbrickable
NVFlash for ICS bootloader
NVFlash for JB bootloader
Warning:
If you flash an incorrect recovery to a 4.2 bootloader there is about a 90% chance that fastboot flash commands will now just freeze the tablet - When you attempt to flash via fastboot everything will seem to go ok on the command prompt but you will not see the blue progress bar on the tablet when flashing & the reboot command will not reboot the tablet after the flash command & nothing will have flashed to the tablet.
If this is the case try this solution.
Please read below for how to check your bootloader version and confirm your flashing the correct recovery.
Requirements:
- Must be unlocked (Method 1 seems to work fine for locked devices but must be unlocked for Method 2 to flash custom recovery).
- Must have working fastboot
- Working adb in recovery (optional). I use adb in this method for rebooting but this can be done manually with vol- & power.
Always make a backup first.
Files Needed:
Download the stock JB firmware you wish to flash from either the Asus website or from the Index thread here, be sure to download the correct SKU version you wish to use On your tablet you can check what SKU your using by going to settings>about tablet, scroll down to build number and you can see SKU version..
If using method 2 download the TWRP recovery you require, Here is a link to the TWRP thread. When you download a version of TWRP it will have a name like "openrecovery-twrp-2.5.0.0-tf300t-4.2.blob" - You can rename to something shorter for flashing if you like, I rename like so "twrp-2.5.0.0-4.2.blob".
What recovery to flash for bootloader version: example for TF300T model:
Check & confirm what bootloader your on - boot to bootloader menu (vol- & power) and look at the text in top left, your bootloader version number is there.
JB 4.1 firmwares
- If current bootloader = 10.4.2.9 - JB 4.1 - recovery to flash = TWRP "openrecovery-twrp-2.5.0.0-tf300t-JB.blob" or CWM
- If current bootloader = 10.4.2.13 - JB 4.1 - recovery to flash = TWRP "openrecovery-twrp-2.5.0.0-tf300t-JB.blob" or CWM
- If current bootloader = 10.4.2.17 - JB 4.1 - recovery to flash = TWRP "openrecovery-twrp-2.5.0.0-tf300t-JB.blob" or CWM
- If current bootloader = 10.4.2.18 - JB 4.1 - recovery to flash = TWRP "openrecovery-twrp-2.5.0.0-tf300t-JB.blob" or CWM
- If current bootloader = 10.4.2.20 - JB 4.1 - recovery to flash = TWRP "openrecovery-twrp-2.5.0.0-tf300t-JB.blob" or CWM
JB 4.2 Firmwares
- If current bootloader = 10.6.1.8 - JB 4.2 - recovery to flash = ONLY TWRP "openrecovery-twrp-2.4.4.0-tf300t-4.2.blob" - flashing a non-4.2 version of TWRP or any version of CWM will brick device. Also flashing 2.5.0.0-tf300t-4.2 on the 10.6.1.8 bootloader results in a split-screen issue.
- If current bootloader = 10.6.1.15.3 - JB 4.2 - recovery to flash = ONLY TWRP "openrecovery-twrp-2.5.0.0-tf300t-4.2.blob" - flashing a non-4.2 version of TWRP or any version of CWM will brick device.
- If current bootloader = 10.6.1.27.1 - JB 4.2 - recovery to flash = ONLY TWRP "openrecovery-twrp-2.5.0.0-tf300t-4.2.blob" - flashing a non-4.2 version of TWRP or any version of CWM will brick device.
- If current bootloader = 10.6.1.27.5 - JB 4.2 - recovery to flash = ONLY TWRP "openrecovery-twrp-2.5.0.0-tf300t-4.2.blob" - flashing a non-4.2 version of TWRP or any version of CWM will brick device.
My Notes about TWRP 2.4.4.0-4.2:
TWRP 2.4.4.0-4.2 will not mount my sandisk 64gb micro SDXC UHS-1 class 10 card, but previous versions of TWRP have no issue. I believe this is a UHS-1 issue. TWRP 2.5.0.0-4.2 has fixed this bug and and can now mount 64gb micro SDXC UHS-1 class 10 card again.
Method 1
- Unzip the firmware zip you downloaded, there will be another zip file inside.
Example:
Lets say you choose WW 10.4.2.20 firmware. (same method apply's for any firmware version and SKU you choose - US, WW, JP, TW, CN)
[*]Unzip "WW_epaduser_10_4_2_20_UpdateLauncher.zip"and you will find another zip inside "WW_epad-user-10.4.2.20.zip".
[*]Now unzip the WW_epad-user-10.4.2.20.zip and you will find a "blob" file.
[*]Now copy the blob file to your android-sdk\platform-tools folder.
Now to the flashing:
- With your device loaded in android go to settings, developer options and make sure they are on & usb debugging is on.
[*]Plug device into PC with usb cable & boot to fastboot.
Using adb commands
Open command prompt (run as admin) & cd to you android-sdk\platform-tools folder.
Check your PC can see your device
You should get a list with you device s/n, if not then adb is not setup.Code:adb devices
Next
Code:adb reboot-bootloader
or
Manually boot to fastboot
Hold vol- & power button to boot to bootloader then connect to PC.
Fastboot will start automatically when connected to PC on the 4.2 bootloaders. On 4.1 bootloaders you will need to select the usb icon using vol- to highlight the usb icon and vol+ to select.
Note:
In bootloader NEVER select the Wipe Data icon or you will brick.
- Once in fastboot open command prompt & cd to you android-sdk\platform-tools folder and type command
and again here you should get a list with you device s/n, if not then fastboot is not setup.Code:fastboot devices
[*]If OK we can now flash the system blob we put in the platform-tools folder
Code:fastboot -i 0x0b05 flash staging blob
This will take about 10 minutes to send & write system, you will see a progress bar on device when system is writing.
[*]When complete
Code:fastboot reboot
This method should work fine but have found that sometimes the device will get stuck at the boot animation, if this happens method 2 works fine every time.
Method 2
- Unzip the firmware zip you downloaded, there will be another zip file inside.
Example:
Lets say you choose WW 10.4.2.20 firmware. (same method applys for any firmware version and SKU you choose - US, WW, JP, TW, CN)
[*]Unzip "WW_epaduser_10_4_2_20_UpdateLauncher.zip"and you will find another zip inside "WW_epad-user-10.4.2.20.zip".
[*]Place a copy of the WW_epad-user-10.4.2.20.zip on your microSD card.
[*]Now on PC unzip the WW_epad-user-10.4.2.20.zip and you will find a "blob" file.
[*]Now copy the blob file to your android-sdk\platform-tools folder.
[*]Now copy the "twrp-version.blob" file you downloaded to your android-sdk\platform-tools folder.
--Make sure you have the correct twrp version for the firmware your flashing.
Now to the flashing:
- With your device loaded in android go to settings, developer options and make sure they are on & usb debugging is on.
[*]Plug device into PC with usb cable & boot to fastboot.
Using adb commands
Open command prompt (run as admin) & cd to you android-sdk\platform-tools folder.
Check your PC can see your device
You should get a list with you device s/n, if not then adb is not setup.Code:adb devices
Next
Code:adb reboot-bootloader
Manually boot to fastboot
Hold vol- & power button to boot to bootloader then connect to PC
Fastboot will start automatically when connected to PC on the 4.2 bootloaders. On 4.1 bootloaders you will need to select the usb icon using vol- to highlight usb icon and vol+ to select.
Note:
In bootloader NEVER select the Wipe Data icon or you will brick.
- Once in fastboot open command prompt & cd to you android-sdk\platform-tools folder and type command.
and again here you should get a list with you device s/n, if not then fastboot is not setup.Code:fastboot devices
[*]If OK we can now flash the system blob we put in the platform-tools folder.
Code:fastboot -i 0x0b05 flash staging blob
This will take about 10 minutes to send & write system, you will see a progress bar on device when system is writing.
[*]Once this has completed type in the command prompt.
Code:fastboot reboot-bootloader
You can now check that your bootloader has upgraded/downgraded, look at the text in the top left of the bootloader screen and make sure it's changed to the firmware version you just flashed.
[*]Now again depending on the bootloader version go to fastboot.
Next
[*]In the below command I am using "openrecovery-twrp-2.5.0.0-tf300t-JB.blob" for JB firmware 10.4.2.20, and shortened the name "twrp-JB.blob" so just change command according to TWRP version needed.
[*]Once this has completed type in the command prompt.Code:fastboot -i 0x0b05 flash recovery twrp-JB.blob
Code:fastboot reboot-bootloader
[*]Now this time in bootloader select the "RCK" icon to enter twrp recovery.
[*]In twrp recovery select "Wipe".
[*]Here I do a complete wipe (cache, Dalvik cache, Factory Reset, System, Internal Storage & Format Data) I don't believe Internal Storage & Data Format are necessary but I like a full clean flash.
[*]Once you have done full wipe type in command prompt.
Code:adb reboot-bootloader
or manually reboot to bootloader, hold vol- and power button.
[*]Now again in bootloader select the "RCK" icon to enter twrp recovery.
[*]In twrp recovery disconnect your device usb cable from PC.
[*]Select "Install" & select the firmware zip you copied to your external sd card and slide to flash/install.
[*]Once completed reboot, you will get message at top of recovery saying there is no OS installed are you sure you want to reboot - slide to confirm yes, another message will popup asking if you want root permissions installed - I select NO "Do not install" you can probably select yes here if you want twrp to root.
The device will reboot, you'll see a progress bar as the signature is being matched, it will reboot again when done.
Now device will boot with the stock JB bootloader & firmware you have chosen.
Done.
You can now flash twrp, then flash any custom rom for that firmware.
As I have said I have done this with all stock WW JB firmware available and can confirm that the bootloader does change and system will boot and run without any issues. But try at own risk.
Firmware I have done this with: Only tried with WW SKU
- 10.6.1.27.5
- 10.6.1.27.1
- 10.6.1.15.3
- 10.6.1.8
- 10.4.2.20
- 10.4.2.18
- 10.4.2.17
- 10.4.2.13
- 10.4.2.9
More Info:
Downgrading from CROMi-X back to CROMi-3.4.6
Upgrading from ICS to JB
If you this information is helpful please hit the thanks button.6Downgrading from CROMi-X back to CROMi-3.4.6
Here are two methods I use for downgrading from CROMi-X back to CROMI (4.2 bootloader back to 4.1 bootloader).
Method 1
- Download the 10.4.2.20 firmware zip - All stock asus firmware zips can be found here - On your tablet you can check what SKU your using by going to settings>about tablet, scroll down to build number and you can see SKU version.
- Once downloaded unzip xx_epaduser_10_4_2_20_UpdateLauncher.zip to a folder & you should find a second zip file, xx_epad-user-10.4.2.20.zip - xx is the SKU version your using, ie WW/US...
- Unzip the xx_epad-user-10.4.2.20.zip and you should find a blob file - this file is the 10.4.2.20 system, stock recovery, kernel & bootloader all rolled into a one blob file.
- Copy this blob file to your android-sdk/platform-tools folder
- The version of twrp you need for 10.4.2.20 would be "2.5.0.0-tf300t-JB.blob" NOT THE -4.2 versions, these are for the 4.2 bootloaders which are firmwares 10.6.1.8 / 10.6.1.15.3 / 10.6.1.27.1
- So download "openrecovery-twrp-2.5.0.0-tf300t-JB.blob" and also put this in android-sdk/platform-tools folder - you can rename it to something shorter if you want, like "twrp-JB.blob"
- Download CROMI 3.4.6.zip and copy to your microSD card.
CleanROM 3.4.6 Inheritance ODEX_Signed.zip
CleanROM 3.4.6 Inheritance DEODEX_Signed.zip
- Now boot device to bootloader (vol- & power) and connect to PC - fastboot will start automatically when connected to PC on the 4.2 bootloaders.
- Open command prompt (run as admin) & check that PC can see your device OK.
Code:fastboot devices - you should see device s/n here, if OK we can flash the system blob we put in the platform-tools folder
Code:fastboot -i 0x0b05 flash staging blob
This will take about 10 minutes, it will send file then write file and you should a blue progress bar on tab when it starts to write.
- When complete
Code:fastboot reboot-bootloader - You should now check that your bootloader has downgraded, look at the text in the top left of the bootloader screen and make sure it's now has 10.4.2.20 - you should now also have 4 icons RCK (recovery), android (cold boot), usb (fastboot) & wipe-data - don't use the wipe data icon in bootloader - it seems to brick tabs.
- So from bootloader screen go to fastboot (vol- to the usb icon - then vol+ to select) and flash the twrp recovery.
Code:fastboot -i 0x0b05 flash recovery twrp-JB.blob
again here you should see a blue progress bar on your tab.
- When complete reboot to bootloader again.
Code:fastboot reboot-bootloader - This time select the "RCK" icon and twrp recovery should boot up.
- I do a full wipe here in recovery then reboot back to recovery again as I also format data in recovery.
Code:adb reboot-bootloader - Now select RCK and boot back to recovery, select and flash the CROMI 3.4.6.zip you put on your micro SD.
- When complete reboot system, Done.
This method should work fine but have found that sometimes the device will get stuck at the boot animation, if this happens method 2 works fine every time.
Method 2
- Download the 10.4.2.20 firmware zip - All stock asus firmware zips can be found here - On your tablet you can check what SKU your using by going to settings>about tablet, scroll down to build number and you can see SKU version.
- Once downloaded unzip xx_epaduser_10_4_2_20_UpdateLauncher.zip to a folder & you should find a second zip file, xx_epad-user-10.4.2.20.zip - xx is the SKU version your using, ie WW/US...
- Here I put a copy of the xx_epad-user-10.4.2.20.zip on my micro SD card. You can also download & copy the CROMI 3.4.6 zip to your microSD.
- On pc unzip the xx_epad-user-10.4.2.20.zip and you should find a blob file - this file is the 10.4.2.20 system, stock recovery, kernel & bootloader all rolled into a one blob file.
- Copy this blob file to your android-sdk/platform-tools folder
- The version of twrp you need for 10.4.2.20 would be "2.5.0.0-tf300t-JB.blob" NOT THE -4.2 versions, these are for the 4.2 bootloaders which are firmwares 10.6.1.8 & 10.6.1.15.3
- So download "twrp-2.5.0.0-tf300t-JB.blob" and also put this in android-sdk/platform-tools folder - you can rename it to something shorter if you want, like twrp-JB.blob
- Now boot tab to bootloader and connect to pc - fastboot will start automatically when connected to pc on the 4.2 bootloaders.
- Check that pc can see your device ok
Code:fastboot devices - you should see device s/n here, if ok we can flash the system blob we put in the platform-tools folder
Code:fastboot -i 0x0b05 flash staging blob
This will take about 10 minutes, it will send file then write file and you should a blue progress bar on tab when it starts to write.
- When complete
Code:fastboot reboot-bootloader - You should now check that your bootloader has downgraded, look at the text in the top left of the bootloader screen and make sure it's now has 10.4.2.20 - you should now also have 4 icons RCK (recovery), android (cold boot), usb (fastboot) & wipe-data - don't use the wipe data icon in bootloader - it seems to brick tabs.
- So from bootloader screen go to fastboot (vol- to the usb icon - then vol+ to select) and flash the twrp recovery.
Code:fastboot -i 0x0b05 flash recovery twrp-JB.blob
again here you should see a blue progress bar on your tab.
- When complete reboot to bootloader again.
Code:fastboot reboot-bootloader - This time select the "RCK" icon and twrp recovery should boot up.
- I do a full wipe here in recovery then reboot back to recovery again as I also format data in recovery.
Code:adb reboot-bootloader - Now select RCK and boot back to recovery, select and flash the xx_epad-user-10.4.2.20.zip you put on your micro SD.
- When complete reboot system & again on boot you should see a blue progress bar, it will reboot once more and load up to android.
- You have now downgraded to stock 10.4.2.20 - you will also have stock recovery so just fastboot flash twrp again, step 13-14.
- Boot to twrp recovery and flash the CROMI 3.4.6 rom zip, reboot, Done.
1
Yeah quite possibly, I didn't even think to try it that way :laugh:
However if just flashing the system blob via fastboot then rebooting, my devices will get to the boot animation screen and just sit there.
I do prefer being on the correct bootloader before flashing the firmware though and this way allows for that.1
To be honest - I'm not sure, I didn't downgrade, let pjc21 say did he. I would be afraid to do mess with file system just like you.
But I would be interested to try this if his downgrading method works.1
Your problem is well known and widely discussed on several forums. To your understanding please Google it firstly if you want to unlock your devise. Here we go:
1. As far as I know V8 does not install at all anymore. V7 will install if you allow "less secure apps" in your Google account settings. On the web - not your Google account on the tablet!
2. Delete the Google account from the tablet (Settings > Accounts), then run the tool again,
3. If that doesn't do it, do a factory reset from Settings, reboot and during the initial setup establish a WiFi connection but skip the google account setup, then run the tool.
This can be a 5 Minute operation that goes without a hitch or a very frustrating experience with lots of error messages. There is no definite rhyme or reason for this. For some people it works like a charm, for others it works after 15, 25 or 55 attempts, for some never....
To check finally if you are unlocked, boot the tablet and read the tiny script in the left corner above. It should say: “The device is unlocked”.
