FAQ

Can the browser version write to a cartridge?

No. The browser versions (TAPE FACTORY / VIDEO FACTORY / RADIO FACTORY) only save a .gba. Writing to a cartridge (WRITE CART) is in the Windows version and needs a GBxCart RW or GBFlash. The Windows version can't load a .gba made in the browser, so if you want to play it on real hardware, make it in the Windows version from the start.

WRITE CART stops with "GBxCart is not responding" or "not recognized"

Usually another tool such as FlashGBX is holding the port. Quit FlashGBX completely (end any leftover python process in Task Manager), reconnect the writer's USB, and try again. Details appear in the SERVICE LOG (click the line display).