IF you need it here are the Stock ROM RUU's
http://shipped-roms.com/shipped/Supersonic/
IF you decide to drop back to stock ROM use either the .1 or .6 RUU
If you are on OMJ 1.5 then either one should work.
Avoid the 1.47 RUU if you can. Also while back on .1 or .6 if you get prompted for the OTA dont accept it.
The latest OTA requires a different root process-for the first part anyway. After that it's still Toast Part II to unlock Nand. (also in Fast's thread I linked).
I'd be surprised if you HAD to drop back to Stock/unroot completely but like I said before, it would ensure a clean start.