The normal EZ-Flash IV lite (deluxe) does support all GBA roms, it actually has better support for it then the G6. Only the compact version doesn't, just like the M3 Pro doesn't. The M3 without pro after it might be an option too, most of it is indentical as G6 (same company), but it uses MicroSD so you don't have such little space...
I'm using a G6, I haven't encountered a gba game that it couldn't play so far.
However the homebrew support is bad, I found a lot of programs that it couldn't run, and still no fatlib for it.