I have been following this thread closely and done like everything needed to try and recover my ST3500320AS 500G Seagate drive with SD81 firmware. Every step works as recommended in Hyperterminal through a RS323/TTL converter. I have even done the "F3 T>i4,1,22" command suggested for SD81 firmware drives. I have also done "F,,22" command and received a "Drive Configuration restored to Default" result. The "m0,2,2,0,0,0,0,22" command yielded, "User Partition Format Successful - Elapsed Time 0 mins 00 sec" - I think this zero time elapse indicates that nothing was done or achieved from the command inserted. With this result I even tried the recommended alternative command, "m0,6,2,0,0,0,0,22" with the same zero Elapsed Time message at the end. My Seagate HDD is still not detected by the BIOS. Back to square one. What else can I do?