is the bios Boot From Media (BFM) it has to be for pbl to work, and as for the key, as long as it is the bfm bios from the usual places then you dont need it, as all the debug bios's use the same key and it is already in the boot.cfg for PBL1.3.5i, i think you might have to use PBL1.3.5i_signed_audio_exploit.zip in the usual places, i used these and have had no problems