R4 Firmware

I can test this theory right now if you want I have a card with AK2 FW on it...give me a second.

EDIT: Nope all I get is "Can not find DS_MENU_DAT" I wonder if M3 Real FW would work. They seem kinda the same. Gotta try that next.

 

If you rename the rom, you have to change the title of the save to match it exactly. Say you have final_fantasy_4.nds, you then change it to ff4.nds. The .sav file will still say final_fantasy_4.sav, so the game will not be able to find the save file. By simply renaming the .sav to match the .nds name, you can easily solve the issue. Instead of final_fantasy_4.sav, it would change to ff4.sav to match the title of the rom.

For formatting, you simply just backup, go to my computer (or w/e you can select the device as a whole depending on your computer's OS), right click the device, and go down to format. Once the window opens up, make sure all the options are fine, and click the format button. It will completely clean the card, done and done. No special formatting tool required or anything.

I personally have not had that issue with the enemies and got myself all the way to Fabul before getting bored with it again (I destroyed it on the GBA, have had a hard time getting in the mood to play it all again). If formatting doesn't solve the lag, then I'm not really sure how to help you there except to say that you'll just have to endure it if you want to play it without buying a hard copy.