Figured out what is causing the menu crashes. You know when the text is too long to fit on screen and it scrolls left and right? When it gets to the end and starts to scroll back, that's when it freezes. This is with the Ozone menu driver, not sure about the others. This also might be occurring because I have made the font a little bigger. This is only happening with
@Crystal's cores.
All the cores works fine, the mGBA core loads but when starting load a game the console just freezes and i have to reset.
The Gearboy core works fine too.
I have the same problem with mGBA, too (only tested one game, though). There was a problem with this core - apparently its dev did not want the RetroArch devs adding speed hacks (or something) to it, that's why the version on the nightlies site has been stuck on like 1.7.3 for years. (Come to think of it, the 81 core has also been stuck on an old version for awhile.) This raises two questions...
1. Why make your project open-source if you don't want people messing with it?
2. Why not fork mGBA? (Nestopia, FCEU, VBA and probably others are forks.)
EBOOT.BIN update could solve some problems...
LINK
Not sure if that will help - AFAIK, the menu data is stored in the core SELF files, the EBOOT (~70 KB) is just a "jumpstart" to the SELFs (4 MB and larger). If the core loads, but the game doesn't, that seems like a problem with the SELF, not the EBOOT; if the SELF wasn't signed correctly it wouldn't even load, it would just crash back to the XMB. Trust me, as someone who until recently was on old firmware I know plenty about resigning RetroArch cores.

Having the menu being coded in each core is not exactly modular programing; it would be better if it was located in the EBOOT (one block of code vs. 40+ identical blocks), but I guess that's how RetroArch is designed.