Tab Mini C boot loop. Help please.

[Pentam]

Something odd happened to my Tab Mini C.
It went into sleep mode and when I looked at it again the next day it said something had failed (don't exactly remember what) and I had the options of "try again" or "factory reset". I selected try again and the device went into a boot loop.

I can get into Recovery mode but only "reboot to system" and "reboot to bootloader" is selectable.
It is possible to reboot to bootloader and it shows up on a PC with fastboot devices.
ADB in recovery shows "unauthorized".

Is there any way to revive the device?
Keeping the data would be great...

[bigwigs]

Originally Posted by Pentam

Something odd happened to my Tab Mini C.
It went into sleep mode and when I looked at it again the next day it said something had failed (don't exactly remember what) and I had the options of "try again" or "factory reset". I selected try again and the device went into a boot loop.

I can get into Recovery mode but only "reboot to system" and "reboot to bootloader" is selectable.
It is possible to reboot to bootloader and it shows up on a PC with fastboot devices.
ADB in recovery shows "unauthorized".

Is there any way to revive the device?
Keeping the data would be great...

Do you have boot.img backed up?
If so, u can use fastboot boot boot.img

Or else you will need to extract boot.img from update.upx

[Renate]

The last update for the TabMiniC was:

Model:  TabMiniC (English)
Finger: Onyx/TabMiniC/TabMiniC:11/2023-11-22_07-26_3.5_946657f755/43508:user/dev-keys
Link:   http://firmware-us.boox.com/0c30bf96b1f58c6884b83b110ab9b880/update.upx
Size:   1,552,092,065
MD5:    0c30bf96b1f58c6884b83b110ab9b880

But we don't seem to have the decode keys for this?
If somebody can, adb pull /system/lib64/libota_jni.so

[Pentam]

Originally Posted by bigwigs

Do you have boot.img backed up?
If so, u can use fastboot boot boot.img

Or else you will need to extract boot.img from update.upx

Yes, I had my TMC rooted, so I had the boot.img backed up.
Tried flashing the original as well as the Magisk-rooted version. Both did not solve the problem.

[Pentam]

Originally Posted by Renate

The last update for the TabMiniC was:

Model:  TabMiniC (English)
Finger: Onyx/TabMiniC/TabMiniC:11/2023-11-22_07-26_3.5_946657f755/43508:user/dev-keys
Link:   http://firmware-us.boox.com/0c30bf96b1f58c6884b83b110ab9b880/update.upx
Size:   1,552,092,065
MD5:    0c30bf96b1f58c6884b83b110ab9b880

But we don't seem to have the decode keys for this?
If somebody can, adb pull /system/lib64/libota_jni.so

That is the version I had installed. Is there a way to flash the whole update via fastboot?
I only know about the method with ADB.

[Renate]

With my Poke3 I've used a custom recovery to flash a decrypted update on a flash drive to the device.
Without userdata mounted it can be hard to find space for 1.5 GB.

If someone has a working TabMiniC we need that libota_jni.so for the keys.

[bigwigs]

Originally Posted by Pentam

That is the version I had installed. Is there a way to flash the whole update via fastboot?
I only know about the method with ADB.

Yes, you can do that using fastboot but someone needs to answer Renate's query about libota_jni.

Those keys need to be updated for tool that allows to extract rom details from update.upx.

[meliori]

Name: libota_jni.so
Size: 11704 bytes (11 KiB)
CRC32: 02478E8C

3B0B382BDA19D0E9F0755C8B01B086DC
A602693F5AF19546BF7F40A523237E54

[Renate]

Originally Posted by meliori

Name: libota_jni.so

Thank you. Added to https://github.com/Hagb/decryptBooxU...r/BooxKeys.csv

[Pentam]

Originally Posted by meliori

Name: libota_jni.so
Size: 11704 bytes (11 KiB)
CRC32: 02478E8C

3B0B382BDA19D0E9F0755C8B01B086DC
A602693F5AF19546BF7F40A523237E54

Thanks for the upload!

[Pentam]

Originally Posted by Renate

Thank you. Added to https://github.com/Hagb/decryptBooxU...r/BooxKeys.csv

Thanks for adding the keys.
I decrypted the update.upx to update.zip.
How do I use the files with fastboot?

[Renate]

You can try with fastboot to boot (not flash) the boot image off the update.
It might break some things, but it might not boot loop.

fastboot boot boot.img

We still don't know why it's looping.

[Pentam]

Originally Posted by Renate

You can try with fastboot to boot (not flash) the boot image off the update.
It might break some things, but it might not boot loop.

fastboot boot boot.img

We still don't know why it's looping.

It gets stuck at the onxy logo with blue LED on in the power button. No change visible.
In the device manager is see a repeated connection of a device "QUSB_BULK_SN:********".


That is different from the repeated loop of screen flashing between the logo screen that I had before.

[Renate]

Originally Posted by Pentam

It gets stuck at the onxy logo with blue LED on in the power button.

QUSB is EDL mode.

You can try Magisk'ing the boot image from the update on another Android.
You can try using an "empty" vbmeta or clearing the flags.

Which files do you have in the update?

I might be able to make something out of the recovery, but that is a bit of work and a bit tedious to do when I don't own one of these.

[Pentam]

Content of payload.bin:
- boot.img
- dtbo.img
- modem.img
- product.img
- recovery.img
- system.img
- system_ext.img
- vbmeta.img
- vbmeta_system.img
- vendor.img
- xbl.img

Magisked boot image did not solve the problem. Same result.
Sorry. Noob here... What do you mean with "empty" vbmeta? Clearing the partition or flashing 0 byte file?