Local Northern California disc drive manufacturer Seagate has discovered a flaw in the “firmware” which controls many of their recently-manufactured disc drives. I was alarmed when I discovered that as many as SIX of my disc drives might be affected, including two of my main production discs in my Mac Pro. These are very high-performance 1 terabyte discs, and despite all my precautions about backups, I was still concerned.
But after following this story closely for a few days and with the friendly assistance of “Brian B.” on Seagate’s tech support live chat system, I finally got what I needed to update my drives. Five of my drives were actually in need of updates…
After about a half hour of nervous hacking, Mission: Accomplished!
I successfully updated five Seagate ST31000340AS (7200.11 1TB drives) which were at SD15 firmware to ‘SD1A’ firmware. This was a little complicated because after I did the two that were internal to my Mac Pro, I had to remove three of my internal drives and replace them with the three from my eSATA drive. It turns out the sixth 1TB drive was actually a Maxtor-labeled drive, and the firmware hasn’t been posted for that drive yet.
But here you go…FreeDOS booted on my Mac Pro running Seagate’s flasher program. Worked like a champ. Whew!

Feb 2 2009 Interesting update found on Macintouch.com written by Randall Voth:
It is my understanding that a log file is written to by the firmware when certain things happen, such as swapping bad sectors. If you startup the drive when it has written exactly 320 items to this log, then the drive will not be recognized at boot. The data is still intact. The physical drive still functions. The log needs to be cleared and you should update the firmware.