Had a look at executables for AR 4.2 and AR / GS CDX v3.3 in ps2dis today and found that the save paths are different.
Action Replay v4.2
Code:
bu00:CODELIST00
bu00:OPTIONS0000
Action Replay / GameShark CDX V3.3
Code:
bu00:CODELIST00
bu00:DATELCODES
I tried editing a save from v4.2 to see if it'd bypass the cdx check when using it with cdx v3.3 but the only ps1 save editor I know of is MemcardRex and it has a few limtations that prevent it as Datel didn't follow the 10 letter / digit format format for the product id / save folder as you can in MemcardRex it just reds the last ten letters / digits
TIONS0000 instead of OPTIONS0000
and
DELIST00 instead of CODELIST00
the save title is also shown as blank instead of Options and Code List, i've tried hex editing the save myself but I just end up currupting it