I got so excited when I found out about your kernel (thank you so much btw, tthis means a lot to me and possibly lots of people who either were nostalgic about this card or couldn't afford any of the "good ones") and decided to use it with my card, I got a Super Card Micro SD in case that matters.
This is the list of ROMs I tried so far
Digimon Battle Spirit: Doesn't work. It seemingly applies the patches and creates a .sav file but it's stuck on a white screen. Patching the ROM with GBATA does nothing.
Mario & Luigi SuperStar Saga: Both games (SuperStar Saga and Mario Bros) work but SuperStar Saga has some visual glitches that make the sprites go translucent and/or blink if I move the character and sometimes during cutscenes. I was so happy when I saw it saved however.
Zoids Legacy: Works fine so far.
Medabots Metabee: Works fine so far.
Baldur's Gate Dark Alliance: Works fine so far
I'll try to test some more roms in the next few days/hours
EDIT:
Digimon Racing: Surprisingly works and saves just fine, not idea why or how this one works but Battle Spirit doesn't. I honestly expected it to be the other way around.
Metal Slug Advance: Seems to work fine, played for a while without any issues. Or at least not that I could notice.
Yo-Gi-Oh Worldwide edition: Works great! No issues whatsoever
KOF EX Neo Blood: It kinda works? There's noticeable slowdowns in the game's music but you can get to the character selection just fine. However, actually playing the game is where issues start happening. There were some visual glitches such as characters twitching mid air and it came to a point both characters froze mid air. The music kept playing but nothing other than the start menu responded.
Medarot Navi Kuwagata Version:
The game works fine. I don't seem to notice any glitches or slowdowns of any kind, however, the game doesn't save. If I save in-game then I don't get any errors and the game says it saved. If I reboot the card/kernel then it shows "saving SRAM to FAT" as it would do with any other game but as soon as I start the game I realize I only the get "Setings" and "new game" options.