The "failure to start" issue is what drove us to upgrade the firmware. We worked the programming over every which way in terms of the start and stop and using the drive status bits to confirm the drive was ready....and yet every so often it just wouldn't start. It was an application that was constantly starting and stopping, so the "infrequent chance" of a failure was more likely than other applications.
Our local AB rep not only connected us with AB support, but actually put us in touch with the guy that was involved in the development of the 525 and the one who actually identified the anomaly that led to the firmware upgrade. He was quite helpful and recommended the use of the Ethernet. When we told him that we had already bricked two drives, he assured us that he had never bricked a 525 that couldn't be recovered via Ethernet. We were quite thankful for that comment because we were assuming that the two bricked drives would need to go back to AB - we recovered them with ease over Enet.