Download the nfsu2_patch_v12.exe from the EA Legacy archive. Run it. This updates your game files and fixes the 6th gear bug.
This crack works by patching the SPEED2.EXE file to completely bypass the CheckCD() function. Instead of looking for the SafeDisc signature on drive D:, it simply returns a "success" value instantly. nfs underground 2 v1.2 no cd crack hoodlum