Analogcog, you are one of the few newbies here who really does homework. You seem to know about as much as I did when I first started posting... Anyway, you cannot save varying size EEPROMs even to a cart with a larger size, just because each game is specifically designed to write to a certain size and use all of it, even if it has to write a whole bunch of 0's. For instance, let's say you wanted to save the Metroid Prime demo over SM64DS, the game would not know how to write to 64Kbit EEPROM. I have also read that this could possibly be a small anti-piracy measure; too bad it isn't a very good one if it is. Also, you mentioned ETool... I cannot stress enough how important of a program it really is; it does everything even down to converting AR saves and oldschool Neo .nsf's to the standard .sav. Whenever I use my MK1, it helps me out by allowing me to back up my real DS cart data, which I find very useful. To any newbie who may be reading this, be absolutely sure to get version 3.13 with the ETcreate, ATxtract, and Max2sc apps with it (included in the .rar from cory's site). And also be sure to get version 3.13 MK4 build to complement these if you also use an MK4.