Seagate has released a firmware revision that addresses continued issues with certain Barracuda and DiamondMax hard drives that have failed for a large number of customers. The problems began with reports of a bug that caused the drives to lock during normal boot procedures. The company on January 16th released firmware that was intended to address the problem, but apparently caused compatibility issues for some users. Seagate claims that any affected drives will still retain the written data despite the temporary inaccessibility.
Potential culprits include the Barracuda 7200.11, Barracuda ES.2 SATA and DiamondMax 22 drives. The latest firmware update supposedly resolves the compatibility issues from the initial fix. More information is available from the Seagate Knowledge Base.