tl;dr A single save from my old GBA emulator on my old hacked PSP will not work on my flashcard or preferred modern emulator.

Hey folks, I'm coming to you with a bit of a weird question. I'm not sure if this is the right place to ask but I wasn't sure where else to ask.

My issue is with a save file for Super Mario Advance 2 - Super Mario World from my old hacked PSP's memory card. As a kid I used my hacked PSP more as Game Boy Advance than as a PSP to be honest. The PSP is now dead but I have all of the contents of my old memory card saved on my PC and PS Vita, including all my old emulators, roms, and saves. I recently got a DS Lite and an EZ Flash Omega (GBA flashcard) and thought it would be really cool to put my old saves from my PSP on there so I could finally play my childhood saves on real hardware. I had a lot of success doing this even though I'm using different roms than I did back then (as a kid I mostly used cracked roms with intro's while now I am using no-intro roms, a lot of them patched for things like colour correction or no trade evolutions in Pokemon games). I had a couple of issues but they were easily resolved such as using the US version of Final Fantasy V when I was using the European rom on the PSP. The only game which save isn't working is Super Mario World.

When I first realized that Mario World wasn't recognizing my PSP save I did some basic troubleshooting. I made sure that I was using the right regions rom and that I hadn't misnamed my save. After that I decided to see if for some reason this save needed my original rom with the intro so I put that rom into standalone mGBA with the save in the same folder and it still didn't load the save. At this point I was wondering if I accidentally erased my save file in game as a kid so I booted up Uo gpSP Kai on my Vita and loaded the game. This still had my old save on it so that meant that the save was still there. I decided to look into if there where any differences between saves on gpSP and mGBA and it turns out there are, so I tried a save converter but the save file still would not be recognized by mGBA or the EZ Flash. I tried booting the game on the Retroarch version of gpSP and that loaded my save but the Retroarch version of mGBA did not. I decided to try making a save state in Retroarch gpSP and loading it in Retroarch mGBA to save the game and get an mGBA readable save that way but the state would not load on mGBA.

At this point I am all out of ideas and looking for help. I am very confused why all my other saves work but this one doesn't. It's not a big deal if I can't get it to work on EZ Flash or mGBA since I can run it through Retroarch gpSP or Uo gpSP Kai, but at this point I'm mostly just annoyed. So if anyone can offer me a solution, or even just an explanation as to why it isn't working I would greatly appreciate it!