Source <a href="http://www.thepernproject.com/">Drunken Coders</a>

This version of the firmware does the following:
The button combination A+B+X+Y, gamecode "PASS" or title "DSBooter" on the GBA cartridge automatically starts program from GBA cartridge (starting from offset 0xC0). To convert an .nds file into a FlashMe/PassMe binary, you need to append it to an nds loader
# backlight fades in
# removes the health screen
# remove RSA signature check for uploading and running NDS files

The big advantage is now you can boot your NDS files from a compatible wifi card with no flash card required (once your firmware is installed that is).

http://ds.gcdev.com/dsfirmware/