I'm suspecting a damaged flash chip. But maybe lolypop000 or kunix can help. Let's see if it can get far enough into the boot to dump regions to a microSD card. It cannot do that with the cure fw loaded, so you will have to flash the original 6.20 fw back to it in preboot. You have that in Loly's repair pack.

Then extract this onto a clean microSD:

[Only registered and activated users can see links. ]

Ensure the unit is fully off by holding on/off button for ~6 seconds. Place card in the unit and turn it back on. If the flash is successful you'll see 'Loader' on the screen and it will try to reboot. Remove the card and see if a file has been created in the root named 41_backup.bin. If it's there, don't upload it yet just advise the outcome.