Hey guys, I know there definitely have to be others like me, who have the FAT PS3s with 256M nands and broke their bluray by downgrading.
The fix for this has already been discovered, IF and only IF you know what blu-rays your PS3 has played. Since these PS3s are quite old, many of them have changed hands. I acquired my FAT used as well and unknowingly downgraded it and lost my playback.
I have discovered that you can "brute force" the DRL files and using FTP I have tried already nearly 100 files...no luck yet but I still have many more to test (I downloaded every DRL pack from the site), I'm sure one should work. I know that there is no "hard lockout" because when I change files I get different errors. A hard lockout, if it exists, would probably only show the "Prohibited Playback" error every time.
I am a programmer myself but I have not developed anything for the PS3 yet...I'm thinking about working on an app to brute force the DRL files, copying and testing each one until one set works. Would anyone else be interested in something like this AND/OR would like to help me create it?