Doe's putting gba roms on flashcarts work?

Well you can put DS roms on a flashcart, but can you put GB/GBC roms on it as well??

Your topic asks for GBA but your content for GB/GBC. So I'll just answer both.GBA: Slot 1 (ds slot) flash cart: No, slot 2 (gba slot) flash cart: yes.
GB/C: Yes, using a homebrew emulator, forgive me but I can't remember the name of it.

Dammit :(

DJ, Flash 2 slotcarts are pretty easy and cheap to come by so dw

Use Lameboy emulator for GB/GBC.