Here's my test results, using the same microSD card:
US Super Gameboy: Works.
JP Super Gameboy 2: Works.
US Gameboy Advance (non-SP): Reboots into last loaded game.
US Gameboy Player on US Gamecube: Reboots into last loaded game.
Has anyone out there gotten v2 working on a non-SP GBA or the Gamecube Gameboy Player?
I found a reason for my problem - it's sd card. EDGB is picky aboud sd cards, but OSv2 is even more demanding.
I started swapping sd cards, and absolutely unbranded 2G microsd card from aliexpress worked! silicon power 8g microsd(hc) booted OSv2 only on classic brick, verbatim 8g microsd(hc) made EDGB to show hex error on power on.
So, now I got OSv2 tested working on: Classic DMG-01, Color CGB-001, Advance AGB-001, Advance SP AGS-101.
Format tool used: windows format to FAT32, sector size 4k.
Card used: noname 2gb microsd card (only one that worked for v2 on every device I could test)