I was just thinking, would it be possible to add a function to the tool, so that when loaded on a 3n1 in a GBA you could backup gb and gbc games by loading some code into the ram to copy the saveddata into part of the reamaining RAM plus a message to be displayed afterwords, swapping the flash cart with the game, waiting for the message, swapping the 3n1 back in, and saving the data to the sd card?
I think it's possible because the GBA has 128kb total of VRAM and 256kb WRAM so there should be more than enough space, as the largest GBC sav I've seen is 64kb.