Don't update if you have a 500 GB drive
I have one of the 500 GB drives affected by this issue according to Seagate's KB article (ST3500320AS, original firmware SD15). My drive updated successfully to SD1A but is no longer accessible by my computer. Head on over to Seagate's community forums or MSFN for an idea of what a clusterf- this is turning into. I hope this gets resolved soon. What's that article on the front page of El Reg about there not being any bad storage anymore...?
Biting the hand that feeds IT
