KT3 Debricking a KT3 Kindle

[teobsn]

Hello there. My previously jailbroken kindle (jailbroken with KindleBreak or WatchThis, can't remember which since I did that was a few months ago and didn't use the Kindle since) seems to be bricked (it is currently stuck on the boy under tree screen with no loading bar upon any reboot).

It used to work just fine a few days ago, until I tried to do some chroot shenanigans which I failed to do properly and most likely I now have a messed up rootfs partition.

So far I've tried to fix it by doing the following things (list is out of order most likely):
1. Let it charge for 24 hours and wait for it to fix itself (as seen on some reddit posts) - doesn't seem to do much, probably won't ever fix itself this way
2. Compiled the following tools: KindleTool, Fastboot-Kindle, imx-usb-loader (imx-usb-loader is only available in other Linux distribution repositories, and my computer mainly runs Nobara Linux, a modified version of Fedora, which doesn't have the package binaries in the repository)
3. Put the Kindle in USB Downloader Mode (SDP) and used imx-usb-loader in order to boot some uboot images (including this one https://github.com/MollySophia/imx6_..._u-boot_kindle , which I managed to compile and which helped me boot the kindle into fastboot - but the image seems to have an android fastboot baked in, since the Fastboot-Kindle tool can't do anything with it, flashing anything or running any command at all returns a remote fail error)
4. Looked at this XDA thread https://forum.xda-developers.com/t/g...eader.4450117/ -- the crackdroid flash guide mentions being able to convert back to dual booting kindle os and android after deleting kindle os if you install android (which could potentially help me with my problem), and the guide does not require a serial/tty/UART connection, but the windows batch file provided in the 8th gen Kindle package does not seem to be able to do that at all - only to install android alongside kindle os

I've been trying to make the Kindle somehow boot into diags mode so I could use the Export Fat option and copy a software update file, but so far haven't been succesful in booting into diags (It would be more easily doable if I had used a serial connection on the Kindle, but I currently don't have a USB to TTY adapter/converter and neither do I have any soldering skills, but I plan on buying one later as a last resort)

This particular thread https://www.mobileread.com/forums/sh...d.php?t=342535 seems to have some useful uboot images which can boot the kindle directly into diags mode but they are all for the Wario Kindles, and since mine is a Heisenberg, obviously don't work (actually tried to boot them, the kindle simply became unresponsive as far as the dmesg errors i receive can help me guess).

I also looked on the following threads: https://www.mobileread.com/forums/sh...d.php?t=343310 and https://www.mobileread.com/forums/sh...d.php?t=341361 (so I could hopefully build a uboot image which boots into diags) but I can't really grasp what's going too easily so far.

Can anyone help me? Is there a better way of unbricking my device (preferably without a serial/uart connection)?

[eddie.t.h]

Without a serial port connection, this will be virtually impossible. You don't even know what's wrong with your device...

[teobsn]

Well, it seems that I've been able to fix it at least partly (and without a serial connection, as I still don't have one). i found an archive (on the CracKdroid Project Chat Telegram group) that was meant for the KT3 and which had a "restore to kindle os" option (combined with booting the android uboot image from https://github.com/MollySophia/imx6_..._u-boot_kindle multiple times until it got into fastboot mode)

The steps were: (Note: I had to do this in Windows)
1. Booting the Kindle into fastboot mode by using imx_usb_loader to boot the https://github.com/MollySophia/imx6_..._u-boot_kindle android uboot image 2 times (I changed the "LP_FASTBOOT_THRESHOLD" in
board/freescale/mx6sl_heisenberg/pmic_rohm.c to a higher number so I had enough time to boot the image twice in order for the fastboot sequence to trigger).

2. Used the fastbootdownload.bat file provided by the script in the "kindle8" folder and pressed 3 on the keyboard (the third option means "Restore system (step 1)" as per google translate -- I don't know the language).

3. The script flashed a restore.img file to the bootloader partition and told me to reboot the device using the power button, which I did, and then flashed some other images as well.

4. The script exited and I ran it again and now used the 4th option and the kindle rebooted into a loading state (The kid under the tree had a loading bar) and then I was greeted by the home screen.

The kindle seems to have downloaded some chinese stuff, but I at least can now have more leverage to play with it further.

The archive itself exceeds the maximum limit allowed by the forum, so I will simply provide its filename (it can be found on the CracKdroid telegram group): kindle8.230118.zip