Taken from g6 user guide:
To enable additional features:
First, please make sure that you have enabled the option of “Enable Real Time” from PC G6 U-DISK MANAGER application. Then press A+B+L+R simultaneously at anytime during game.
A “Special Effect Menu” will come out after press A+B+L+R simultaneously during game running
SAVE - Save all the contents of GBA into Flash Memory of G6flash
LOAD- Restore the saved contents to GBA from flash memory
SAVE BACKUP1
LOAD BACKUP1
SAVE BACKUP2
LOAD BACKUP2
RESTART Return to the beginning of game
MAIN MENU Back to Main Menu