I've got a ADL 528, (Don't laugh, i've replaced it with a pioneer 350 !!)

I knacked the firmware on it and need to re-flash it back to the original.

Can't use the normal method as the machine won't start up so need to link it to something else (link a pc) and flash it that way (somehow)

Alternatively, if anyone has a broken 528 lying round, but the motherboard is okay and the firmware is intact, could they sell me it.....

Trying to do this as a project, but don't have much knowledge of electronics,