@unisoft ,
Do we know the versions of the bootloader that causes this issue ? i can provide Dumping Firmware for anyone that has this new Bootloader , it's just patched official firmware that dumps the entire flash to serial UART0
I can also beta test(but not had issue, will be tester for new bootloader if we can dump it) as my riden is still hooked up to my stlink and my bootloader is patched to not lockout SWD but otherwise is factory so i can even dump ram values etc, I have my own bootloader too that is fully compatible with most and somewhere I also wrote debug firmware to give feedback on the lcd (it goes through various LCD types INIT routines , works so long as GPIO used does not change)
As for the white screen my first idea is the bootloader leaves the screen/gpio in a mode that your firmware does not undo , Am looking at the older bootloader and it does look at power button and if held it skips other checks and jumps to Entry vector of new code. maybe in a debug version you could add a check to "skip" lcd init(button one for GPIO, button two for just LCD init routine, both for both) and assume the bootloader did it , i know in the first bootloader i got my hands on it did not do lcd init if the crc of the end of flash was correct , it would only do that if you held the bootloader key on power up or the MAGIC value was in ram. Later version would setup lcd to a black screen regardless of bootkey or MAGIC value.
I will see if i can find the later bootrom , it was not from any of my devices but another user who had issues getting it to accept any update but one, so i patched that for the dumping procedure and we managed to sort it by clearing some values at the end of the flash.
darkspr1te