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How To Guide Lock+Unlock Bootloader - Xiaoxin Pad Pro 2021 [TB-J716F]

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sebseb83

Member
Nov 6, 2021
11
3
Ive got TB-J716F bought from bangood. I want to put it back to stock google or something that isn't chinese based but I am having so much trouble. I can't even get an IMEI number from this thing. There is no IMEI on the box, in the settings, anywhere. I have tried to flash another rom but I can never get it to go into EDL mode. Any ideas? thanks

Just now I even downloaded an app to tell me the IMEI number and it is blank where it has IME1 and IME2
 

Tropaion

Member
Jan 4, 2021
45
43
@sebseb83 There isn't any "Stock Google" or whatever you want.
With a bit research you should know that this tablet is only sold in China and at Stock there only exists the chinese rom.
Only devices with cellular connectivity have an IMEI number, which this tablet doesn't have.
 

sebseb83

Member
Nov 6, 2021
11
3
@sebseb83 There isn't any "Stock Google" or whatever you want.
With a bit research you should know that this tablet is only sold in China and at Stock there only exists the chinese rom.
Only devices with cellular connectivity have an IMEI number, which this tablet doesn't have.
Makes sense, thanks. Yeah I meant the international rom, sorry its 3am here.I have been doing my due diligence I can pick up devices when I am connected in Windows using adb devices, but whenever I try to boot to EDL I can no longer see it and nothing works, Ive tried several other ways to get into EDL with no luck... with the images attached, is that normal? To be honest, the ROM isnt so bad and I guess I could live with it, but I just don't trust it so would rather have installed the rom myself is all. I got no clue where to go from here. I might just have to take it for what it is!
 

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sebseb83

Member
Nov 6, 2021
11
3
@sebseb83 Did you install Qualcomm Drivers? In EDL Mode the screen stays black, thats normal.
Hey,

Sorry was pretty vague with my last comments, I think I was just spending too much time and was too tired to think logically.

Stepped away for a bit and came back to see what I need to do.

I believe I have the international rom as it is all in English, does not have Chinese bloatware installed and came with the Google Play Store. My bootloader came unlocked which I don't like as I am not sure anything else may have been installed in the background that could steal information etc.

So basically what I want to do is put this back to stock which I believe I need for OTA updates. Currently still on Android 11 and Security patch is from April. For the updates I believe I need to lock the bootloader again. I tried the script several times with the device started and in fastboot mode. It just sort of seems to hang after going into bootloader and the command prompt stays at < waiting for any device >. And yes I have the Qualcomm v1.0 driver installed and USB Debugging enabled. Not sure If I am doing anything wrong here, any other tips on what I can try to lock the bootloader? I want this thing as Vanilla(safe) as possible, thanks.

EDIT: Another weird thing is that it doesnt seem to hold the time/date I enter manually into the tablet. It always reverts to September 1, 2033. And my serial number looks a bit short. the ZUI website keeps saying it is invalid.
 
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sebseb83

Member
Nov 6, 2021
11
3
Well I had some progress. I used the Lenovo driver from zeroflame15 in the first page of this post, and straight away when I went into bootloader and did 'fast boot flashing lock' it seems to have worked, advised me I can lock the bootloader and I must select yes and i will lose all data... no problem. The very second I did that, it came up with some corrupt message and to visit https://support.google.com/android/...18740835400736-536875921&p=verified_boot&rd=1

Now my device is stuck in fastboot, no matter what I do, it always stays in fastboot... have I really screwed this up now? Tablet is brand new, all I wanted was a vanilla experience, now it looks like I may have bricked it. Any help would be really appreciated, thank you.

EDIT: I still have fastboot access at least, so hopefully not all is lost. I thought I would maybe try to unlock the bootloader and see if that does something but I can't get an sn.img for ZUI website as I don't have an IMEI number. Any ideas how I can get this image? Thanks.

EDIT: I somehow managed to fix this. I thought it was a goner for sure.

It's not the Android I had when I got the tablet, it seems to be the ZUI Chinese rom, which I am going to hopefully get rid off somehow. All I want is vanilla Android(if possible) but if anyone else gets stuck in the bootloop like me, translate this, it is in Chinese but you get the drift...

 
Last edited:

zxcv88

Member
Oct 4, 2021
31
33
Hello to everyone, can someone post the exact steps on how to lock the bootloader?
Thanks
You need to be on official Chinese ROM first. @Tropaion made a tutorial on how to flash it.
For locking the bootloader you need to enable USB debugging in developer settings.
Then plug in the tablet to your PC, open adb shell and type "adb reboot bootloader"
After it's rebooted to the bootloader type "fastboot flashing lock"
Then you're done and can reboot.

Few things to keep in mind: never unplug the tablet when flashing ROMs. Also the locking bootloader command doesn't always work and you might have to try a few times or switch between fastboot and bootloader.

Hope this helps, there are also a few topics on locking/unlocking if you're stuck.
 

markopololol

Member
Dec 30, 2014
7
1
Hi guys

Struggling here. I have downloaded the lenovo driver and used the "LockBootloader.bat" script and followed the prompts. It shows device is now locked but I cannot get out of fastboot mode. It just bootloops like the other guy, but I am not clear on the fix?

Any help would be appreciated.
 

markopololol

Member
Dec 30, 2014
7
1
So I ended up just following the instructions here to flash the chinese rom. Looks like the bootloader did lock from the script here. I had the fastboot issue describe later on, but I didnt have to rerun the bootloader locking steps.

It restored Widevine L1 which was the goal so happy with that.
 
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    How To Lock and Unlock Bootloader - Xioaxin Pad Pro 2021 - TB-J716F

    Since I found out that the Tablet supports Project Treble I'm trying to get a GSI-ROM running on it.
    Currently with many trial and error I got LiR-ROM to boot.
    The first step is to unlock the Bootloader so I thought I will share the process here.
    Your data will be deleted while unlocking, try it at your own risk.

    Unlock Bootloader manually
    Requirement: PC with ADB Fastboot
    1. Go to Settings -> System -> About Phone, tab on it until developer settings are enabled.
    2. Go to Developer Settings and enable "USB Debugging" and "OEM Unlocking".
    3. Open Console and enter "adb devices". Allow USB-Debugging if tablets asks.
    4. Enter command "adb reboot bootloader".
    5. Write down the serial number shown on the bootloader screen
    You can either get the unlock image via this link "http://cdn.zui.lenovomm.com/developer/tabletboot/[your sn number]/sn.img" or via the webseite
    5. Go to the ZUI Unlock Website and request the unlock image

    ZUIUnlock.png


    6. You should get a mail where you can download a file called "sn.img".
    7. Flash the image with fastboot "fastboot flash unlock sn.img"
    8. Enter command "fastboot oem unlock-go", bootloader will unlock now.
    9. Restart with "fastboot reboot".
    Done, your bootloader should be unlocked now.

    Lock and Unlock Bootloader with Batchscript
    I recently found a batch script for lenovo devices in an chinese forum and translated it.
    It's easy and convenient to use. For unlocking you still need the sn.img from the ZUI Unlock Website.
    Download BatchScript
    4
    @sakun-ice I got LineageOS to run on it today, but it still has 2-3 bugs.
    4
    Thanks @zxcv88

    After installing the lenovo USB driver, the !Android in Other devices was updated.

    Boot into bootloader mode and "fastboot flashing lock" runs without any issue

    Appreciate all for the advise and help! Appreciate ~
    2
    Hello to everyone, can someone post the exact steps on how to lock the bootloader?
    Thanks
    You need to be on official Chinese ROM first. @Tropaion made a tutorial on how to flash it.
    For locking the bootloader you need to enable USB debugging in developer settings.
    Then plug in the tablet to your PC, open adb shell and type "adb reboot bootloader"
    After it's rebooted to the bootloader type "fastboot flashing lock"
    Then you're done and can reboot.

    Few things to keep in mind: never unplug the tablet when flashing ROMs. Also the locking bootloader command doesn't always work and you might have to try a few times or switch between fastboot and bootloader.

    Hope this helps, there are also a few topics on locking/unlocking if you're stuck.
    2
    @zeroflame15 You have to be in bootloader mode. <waiting for device> is propably the driver.