Hi, thanks for getting back to me.
I can say for a start that I also experience this problem when using a microsd card plugged directly into the unit.
I take your point re: the custom rom but it would seem to me that if it's possible to find and scan one track into the library, it should be possible for it to do them all.
Case in point, tracks that were previously in my library are now omitted following the full rescan. None of the filenames or locations have changed.
I can access and play all the files using the headunit's file manager, it only seems to be Poweramp that h