You have a new ds, correct, so that's why you want to install the flashme firmware?? The firmware test is here, assuming you haven't run it already:
http://www.neoflash.com/forum/index.php/topic,1565.0.htmlIf you have a newer ds, you need a PassMe2 device in order to install the flashme firmware on your ds. Your mk3 would not be able to do this, since it's not directly compatible with new ds systems.
The dspassme site has the details:
http://www.dspassme.com/You buy a passme2 device pre-configured for a game you already own. You write the SRAM data for that game to your gba cart. You flash the flashme application to your cart, insert your passme2 device (with game cartridge inserted) into your ds, and then you turn on your ds to install the flashme firmware.
BruceG