I am also curious, as I also own an EZ-Flash IV. (Fat GBA SP kind)How can I play gba games on an emulator with saves from the EZ Flash 4 and viceversa?
Thanks^^
File pulldown menu -> Import -> battery file
File pulldown menu -> Export -> battery file allows you to send it back.
This works for most GBA flash carts. Certain carts when used with things like AKAIO will have an extra header added onto the save to allow AKAIO to work more easily, you will need to remove this.
Alternatively you may also have to pad out or trim some GBA saves to match what VBA thinks it should be.