As expected, Crucial released a firmware update, version 0309, to fix the bugs affecting the M4 SSD after 5,200 hours of uptime:
http://www.crucial.com/support/firmware.aspx
To apply this update on Mac OS X, select the firmware corresponding to the storage capacity of your M4 model; then burn the ISO image to a CD, boot from it and follow instruction.
Remember to do a backup of your SSD before conducting any firmware update.
