3DS | GBA games save management via GodMode9
NOTE: this method was tested using GBA games installed via CIA files.
GodMode9
First of all, it’s a relative new feature, so be sure to have GM9 updated.
To update it, you can follow the process over GM9 github page. Alternatively, it is possible to update it via Universal Updater Homebrew, which I consider way easier.
Backup and inject
To make a backup/inject a save, you need to have that game installed. Run the game until it sarts (until it is playable) and close it / turn the power off. This step is EXTREMELY important. Imagine it as if you were injecting the cartridge to the console.
Now, pressing the START button, turn your system on to launch GM9.
BACKUP
To backup the previous opened game, choose SYSNAND VIRTUAL -> agbsave.bin. The lower screen should have AGBSAVE options… option. Select it and Dump GBA VC save. The backup file can be found at the /gm9/out/ directory on your SD’s root.
INJECT
To inject a save to a game, considering you already have the .sav file somewhere inside your SD, navigate to it under SDCARD. Press Y on top of the selected .sav file to copy it to clipboard. Now navigate back to the GM9 root screen and select SYSNAND VIRTUAL -> agbsave.bin. The lower screen should have AGBSAVE options… option. Select it and Inject GBA VC save.