Kept having read problems with commercial dvd's...but only after upgrading the firmware on the 812s to USOQ... the drive would never spin up to the faster DVD speed I used to hear. Very rarely would a disc that refused to read suddenly be recognized and usuable. Decided that the new firmware upgradge may have been the problem, so re-flashed with an older version, USON. Voila'! Suddenly I have no problems recognizing and reading all the commercially produced DVDs I had been having problems with. Don't have a good guess as to why, but -- for me, the newest firmware seemed to have compatibility issues with my Emachines XP machine. Don't really care why, just glad this down-flash solved my problems.