One of our Dell Latitude E7240 exhibited strange mSATA SSD behaviour. Disk requests didn’t complete on time. This computer ran the A13 firmware.
The case was eventually solved by upgrading to the A21 firmware executed from an USB stick as the mSATA SSD was unreliable at this point. Apparently, the A18 firmware corrected some mSATA port settings. Also, this was a good opportunity to rid us of Intel’s SA-00075.
This isn’t the first case where disk behaviour suddenly changes to the worst on Latitude E-series laptops, only to be rectified by a firmware upgrade.