Flashing slot b went smoothly, the system booted into it on restart. Locking the criticals also went well.
But when I tried to lock the bootloader, I got the “your device is corrupted and will not boot” message and got stuck in fastboot mode. Following @AlphaElwedritsch’s instructions from a related thread, I unlocked the bootloader and tried reinstalling from scratch. I flashed the recovery.img to both slots and flashed the custom key, but I’m still stuck in the bootloader.
Volume up + power, fastboot reboot recovery and selecting recovery from the bootloader menu all bring me back to the bootloader menu.
Please, if anyone knows a way out of this, I’ll be very grateful.
EDIT 1: It’s OK, changing the current slot got me back into iodeOS. I’ll try sideloading the iodeOS *.zip from this slot.
EDIT 2: Sideload ends with the following error in the terminal (no errors in recovery screen):
serving: ‘iode-2.4-20220407-FP4.zip’ (~94%) adb: failed to read command: Success
The phone booted off the previously corrupt slot. I did a dirty flash, so all settings were retained.
So I definitely have one of these un-relockable phones, whether it’s a HW or FW thing, something is different in these newer batches. I bought my phone only a week or so ago. It’s a shame I can’t lock this phone down.
Thank you, @vince31fr, for your help.