There is a particular version of the firmware (SD15) that is buggy, and has resulted in a very high level of drive failure. Older (and newer versions) do not suffer from this problem.
If you have the SD15 firmware on your drive, Seagate advise that you update the firmware to SD1A - the update is available for download from their website.
Once the firmware bug strikes, and the drive locks down - it can't be flashed, and the drive must either be RMAd, or sent for data recovery (Data recovery is usually successful, as the firmware bug results in the drive incorrectly entering 'safe mode' in an attempt to preserve the data on the platters. In safe mode, the drive is completely locked down and unresponsive, so that the platters do not get touched until the drive is repaired; hence why it cannot be flashed once in this state).
Note that the firmware bug is very specific - the bug prevents the drive being detected in the BIOS. The drive will spin up, but will not be detected during boot up.