Got it! The ROMs are good but there's a broken pin in the SnapSCSI preventing it from properly connecting with the logic board.

Will replace it and it should be up and running again...

On the other side, tested the SnapRam card and it is working great, giving me a whole 1MB to my 512K!!! 

By the way, anybody knows if a 50 pin connector can be installed in the corresponding 50 holes in the SnapSCSI card so to gain internal SCSI? I hope it works so I can install a SCSI2SD card inside the 512K.