FWIW, there are reports on XDA forums (
http://forum.xda-developers.com/forumdisplay.php?f=2036) of some HD+ units getting bricked after using the LagFix(fstrim) app (from the GooglePlay store), or after installing/running some recent builds of (Android 4.3 based) CM10.2 that have the built-in fstrim enabled.
I'd suggest staying away from the LagFix app, and doing very careful research in selecting a CM10.2 build to install/use (similar precaution applies when buying/updating pre-made SD card images of CM10.2).