SSDs are complex beasts :-)

I've had an OCZ SSD in the past that also became read-only, in the sense that all changes after shutting down the computer were gone.

If you rebooted everything was fine, but as soon as the computer was shut down and the SSD also ran out of power, it converted to the state before turning on the computer. That was so bizarre. Once I had a hefty Windows upgrade installed and it was gone after the reboot - as if I had never installed it. It also took me a while to realize it because first of course you start to doubt your own memory, you don't realize that the sector- mapping on the SSD has suddenly become read-only

OCZ eventually solved this via an RMA and eventually OCZ also went upside down. The Time Warp bug it was called I think.