See my post here: Re: Using SD Adapter with Action Replay on GC in 2019.
The readout of the patching program after being run is identical to gtmtnbiker's quote above
Action Replay Gamecube/SD Loader Problems
Re: Action Replay Gamecube/SD Loader Problems
Thanks a lot! The upshot is: you MUST have windows XP to run SDpatch.exe, and you MUST use this process for older versions of Action Replay. Most of the tutorials online right now are leaving out that all-important detail!