If you’re using Doom 3 BFG Edition backup and a patch to run it on your 3.55 firmware PS3 and get a blank black screen, don’t get upset.
For some reason, the backup has subfolder names in lower case, which is not common for PS3, and if you copy it to internal drive using File Manager
in multiMAN, it will convert all lower case subfolders to upper case. And you will probably be copying the patch over FTP, resulting in subfolders with identical names but different letters.
To make it simple, just copy the backup folder to GAMES folder on FAT32 formated USB drive and replace the required files in corresponding folders
with the patched ones. No plug this drive to the console and find the game in multiMAN game list, press triangle on it and select Copy to copy
the backup to the internal drive. After copy process completes, find the HDD copy of the backup and run it as usual. The game should run
fine now, just don’t update to 1.01 or it will screw everything up. If you still can’t launch the game from internal, try mounting the external USB
copy in BD mirror mode, that is pressing Select-X on the gamepad.