With this tool you'll be able to extract individual saves from an sram dump from a GB USB Smart Card 64M flashcard loaded with MottZilla's menu.
Since version 1.1 you can also inject saves, so you are able to transfer save files from other devices into the flashcart with ease.
However, this functionality is limited to replace a existing save, so you have to first run the game in the flashcart and power cycle your gameboy to allow the menu create the save and then transfer the sram to your pc to replace it.
How to use:
Open an sram dump from a GB USB Smart Card 64M with menu.
Select if you want to extract a save or inject a save.
Double click the save you want to extract/replace from the list.