I get to that select screen, but the only file I can select is the PSX4ALL rom I mentionned in my first post here. However, it is not in MyDocs but in MyDocs/Roms/PSX.

Now I have another serious problem, not related at all I suppose: my N900 is chain rebooting. It occurs unplugged (no way to get the PIN code screen), USB plugged, and it even occurs when booting in BackupMenu mode (I can actually see the menu and I can navigate, but it finally reboots after several seconds). It really worries me because I'm affraid this is CPU-related and I see no way to fix it since the problem persists when the phone is USB connected, thus I can't flash it.

The world's against me. :|