Crucial M4 SSD 2.5
Downloaded from their site Crucial.com Product Downloads - Firmware Updates
A friend found this in the M4 firmware release notes:
Correct a condition where an incorrect response to a SMART counter will cause the m4 drive to become unresponsive after 5184 hours of Power-on time. The drive will recover after a power cycle, however, this failure will repeat once per hour after reaching this point
. The condition will allow the end user to successfully update firmware, and poses no risk to user or system data stored on the drive.
This firmware update is STRONGLY RECOMMENDED for drives in the field. Although the failure mode due to the SMART Power On Hours counter poses no risk to saved user data, the failure mode can become repetitive, and pose a nuisance to the end user. If the end user has not yet observed this failure mode, this update is required to prevent it from happening.
A big thank you to Anthony, for sending me in the right direction.