Are you sure it was a PRL not a PRI update? Was the program you used in the connections tab? Your only hope with this
AFAIK is to do a ##RTN#, (make sure you know your MSID and MDN) which to access you may have to install the sprint carrier cab, and then enter ##(your previous MSL). Reprogram the phone. I would ask Sprint to walk me through this unless you are very experienced. Once you have ##code access, I would leave off the rest about any custom roms when speaking with Sprint. Good luck.