Or change the setting of the byte which is always the best
Often it's
Call IsCDInserted
Test EAX, EAX
Blah Blah
You can just patch the "CALL IsCD" into "MOV EAX, 1"
which a) perfectly works (unless there's an additional check based on booleans -> bytes)
and b ) eliminates the CD check phyisically, hence it starts earlier than normal as it doesnt need to search for drives, checks etc.