Yeah, I did that previously. Not working for me. Tried holding R before L (emu menu button), tried pressing and releasing R before L, and also using the game's exit menu option after pressing R and then going back to the emulator to Hard Reset or load another game to see if it worked, and nothing.
A quick game to test is Metal Slug 2, you can change lives or difficulty and go back, and it will ask you to format the Memory Card.
I'll try creating a working save file with A3 and try to load it in A2, just to check.
EDIT: Nope, not working.
A3 on the other hand doesn't need manual saving with the button. It always saves and loads the next time.