Dead battery and bootloop. System files corruption?

  • Hello,

    I had a dead battery after more than 2 years of heavy use. I've bought one on ebay and it lasted 2 months, when it started to turn off suddenly. Now the phone turns on, i can go even in the recovery menu, but when i turn it on normally it goes on bootloop.

    is the system now corrupted because of the sudden switch off? Or is the problem just the dead battery?

    in case of corruption, can i flash just some partitions with fastboot in order to maintain data and do all the necessary backups? Which ones?

  • MVP

    If your M5's bootloader is locked, you won't be able to flash anything at all.

    First of all, take off the SIM cards and SD card (if you have one installed) and try to boot into secure mode following the steps described in this link:

    Best regards

  • thank you for your fast reply,

    I'm keeping the volume down button as described in the link, but the animation keeps going on and on... already 2 minutes gone 😞

    Until it reboots...

  • MVP

    This is your best opportunity yo recover something. You have to begin pushing the button just in the moment that the animation begins, not before.

    The other thing you can try to recover the phone functionality vwould destroy all the data: Factory Default Reset from Recovery.

    Best regards.

  • Is there any way to install again the system files like i did whren i've downloaded the update? Because in the recovery i can select "update from ADB or SD card"..
    (I've tried also just after the animation start but nothing has changed...)
    I've downloaded the fastboot firmware, and inside there are every partition as image files. What if i flash one by one except the userdata? (of course after having unlocked the bootloader)

  • MVP

    @uociuca the bootloader lock won't let you flash anything. You would need to unlock it thus allowing to flash, and that process (unlocking) will cause a wipe user data.

    Anyway, the partitions into the fastboot compressed file are not flashable through fastboot.

    I'm so sorry, but you have not much options to recover your data unless your device boots.


  • Thankyou... I've missed this part "that process (unlocking) will cause a wipe user data."...
    Last request before proceeding with full wipe. Where can I download the OTA packages and emulate an update process? Could it work?

  • MVP

    Sorry, he OTA packages are not available as public download, only the fastboot firmware is available.

    Best regards

  • OK. I try to contact the support directly, maybe they manage to provide me that package (i hope...)
    Thank you anyway for your kind support!

  • MVP

    @uociuca nothing at all, and I wish you have good luck with your problem.

    Best regards.

  • Hi again..
    I'd like now to unlock bootloader with the code I saw I have to request to a moderator sending the SN with a PM.
    Can I ask it to you? And how to use it?

  • MVP

    @uociuca I'm not a mod : P

    Use this link to contact support and ask for the file.

    Best regards

  • Hello again,
    Today I had time to experiment and.... DID IT! It's possible to recover data 😄

    These are the steps i've followed, if someone has my needs:
    1. download your firmware package from page support and extract everything (it contains all *.img files and fastboot/adb exes)
    2. download the last TWRP recovery image
    3. unlock the bootloader with the JSON provided by support and the BQ firmware flash tool
    4. DON'T continue with the firmware flashing and keep your phone turned on
    5. flash via fastboot the SYSTEM, BOOT and RECOVERY images contained in the firmware package downloaded
    6. now boot to the custom recovery with the command "fastboot boot twrp.img"
    7. as soon as you get in the custom recovery adb is enabled, so you can access to your phone internal storage and pull every folder you need (/sdcard in my case)
    8. after you are done, go back to bootloader and with BQ firmware flash tool flash the firmware (now the bootloader will lock again so it performs a full wipe)
    9. after the phone boot up, turn off it again and unlock again the bootloader as in the 3rd step
    10. boot again to custom recovery and push with adb the folders you have saved before and change the permission with the following following (then reboot to system):
    chown -R media_rw:media_rw /sdcard/
    find /sdcard/ -type d -exec chmod 775 {} ';'

    find /sdcard/ -type f -exec chmod 664 {} ';'

    I don't know if there's a shorter way to recover data, but to me was important the purpose 😄