I never could get the DVD player exploit to work, so I ended up buying a memory card with with FreeMCBoot.

I get the feeling that the DVD exploit is fiddly and requires adjustments for each iteration of the possible PS2 hardware configurations.

There are many different revisions of the DVD player software, requiring specific offsets for each exploit. The SPRs (system parameter registers) exposed in DVD player scripting do not expose enough information to be able to merge the exploits onto one disc.

FreeMCBoot continues to work, but is no longer updated. I would recommend https://ps2homebrewstore.com/ to check out the latest exploits and devices available, such as sd2psx, an open source reimplementation of a memory card that can also expose the filesystem on its inserted SD card.