My Tecno Spark 10 Pro (MediaTek Helio G88, Android 12) bootlooped after a banking app froze. Now it boots straight into stock recovery with the message that Android cannot be loaded and data may be corrupt. The bootloader is unlocked. I hooked it up to an Android tablet via OTG with Bugjaeger. The device uses A/B partitioning and was running on slot b. I switched it to slot a via fastboot, but slot a gives the exact same recovery loop, so the issue is clearly a corrupted userdata partition failing to mount during early init. All I need is my local KeePass database file from internal storage. I know modern Android uses File-Based Encryption with keys sealed in the TEE, but since my bootloader is unlocked, is there any known way via fastboot, MTK tools, or custom boot images to extract or decrypt that single file before I wipe the device? Or is it completely unrecoverable once the filesystem fails to mount?

My Tecno Spark 10 Pro (MediaTek Helio G88, Android 12) bootlooped after a banking app froze. Now it boots straight into stock recovery with the message that Android cannot be loaded and data may be corrupt. The bootloader is unlocked. I hooked it up to an Android tablet via OTG with Bugjaeger. The device uses A/B partitioning and was running on slot b. I switched it to slot a via fastboot, but slot a gives the exact same recovery loop, so the issue is clearly a corrupted userdata partition failing to mount during early init. All I need is my local KeePass database file from internal storage. I know modern Android uses File-Based Encryption with keys sealed in the TEE, but since my bootloader is unlocked, is there any known way via fastboot, MTK tools, or custom boot images to extract or decrypt that single file before I wipe the device? Or is it completely unrecoverable once the filesystem fails to mount?

  • hexagonwin@lemmy.todayEnglish
    1·
    29 days ago

    ok. in that case you can unpack that boot image, edit default.prop in ramdisk like i mentioned above and try fetching logcat.

    i’m away from my workstation for a while so i can’t edit the boot image for you now. you can try it yourself, or if its fine please wait a few weeks

      • hexagonwin@lemmy.todayEnglish
        1·
        16 days ago

        sorry for keeping you wait for so long. please try downloading this boot.img file and booting it. i’ve modified the original boot.img’s default.prop to enable ADB.

        boot that using fastboot boot tecno-ki7_boot_adb.img, and right after that run sudo dmesg -w to see any new USB device appearing. Also open another terminal and try adb devices, adb shell etc and see if you can communicate with the device while it’s in the boot animation stage.

        if the new boot.img i provided doesn’t work please let me know, we might need to nullify vbmeta

        • lipen@reddthat.comOPEnglish
          1·
          4 days ago

          Hey! I found a little bit of time to try it out! Thank you very much for trying to help me! When I trying to boot it up I getting:

          fastboot boot tecno-ki7_boot_adb.img
Sending 'boot.img' (26862 KB)                      OKAY [  0.655s]
Booting                                            FAILED (Status read failed (No such device))
fastboot: error: Command failed

          and logs from dmesg: https://0bin.ch/?51a49ed0a5778a18#DPxaTLsafGXC2jEokDCF5mZ2YiexKJHoYkz7GCthwMNa Also adb devices and adb shell does nothing.

          • hexagonwin@lemmy.todayEnglish
            1·
            4 days ago

            hmm that’s weird.

            after the fastboot boot command fails, what does the device show on screen? is it stuck on fastboot? or reboots?

            perhaps doing fastboot boot as sudo might help.

            did you install fastboot from your linux distro’s repo? what version is it? (it might be very outdated and be the cause of issues)

            • lipen@reddthat.comOPEnglish
              1·
              4 days ago

              After fastboot command device reboots and trying to start android, I think and then just shows me error screen again. Yeah, I tried sudo, but didn’t help. I tried 37.0.0 version too and result the same. Idk this phone is cursed.

              • hexagonwin@lemmy.todayEnglish
                1·
                4 days ago

                in some cases i’ve seen fastboot command return error on console but actually succeed in executing the wanted behavior, so it might be the case here that our boot.img did successfully boot.

                by ‘device reboots and trying to start android’, do you mean the device actually rebooted again to bootloader stage (e.g. vibrate and show manufacturer logo), or just boot android without that step? an easy way to confirm this is by holding fastboot or recovery hotkey right after fastboot command. if it did reboot and start again from bootloader it will enter fastboot/recovery, but if it didn’t and actually booted our new boot.img it would just boot android

                • lipen@reddthat.comOPEnglish
                  1·
                  4 days ago

                  after fastboot boot error I immediately held volume up and the phone showed TECNO logo and then went to “No command” screen.

                  • hexagonwin@lemmy.todayEnglish
                    1·
                    3 days ago

                    hey can you confirm that the original unmodified boot.img doesn’t return failed while the new one does?

                  • hexagonwin@lemmy.todayEnglish
                    2·
                    4 days ago

                    ah, damn. it seems like it completely failed to boot…

                    i’ll try another go at making a new boot.img and let you know soon. kinda out of ideas at this point tbh.