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Crucial released a new firmware upgrade today for Crucial M4 SSD owners to prevent occurrences of the 5200 hour bug.
The firmware can be found here and applies to all capacities of the Crucial M4 SSD. The bug itself would affect the m4 through an incorrect response to the SMART counter after 5184 hours of power on time and the SSD would become unresponsive thereafter. This firmware is STRONGLY RECOMMENDED for Crucial M4 owners.
The only exception would be if you are using a RAID controller with a SAS expander. for us, please wait for update unless you are experiencing problems. 🙂