I have mario bros3 mix working and i just injected it normally are you using a bad rom.I'm having issues getting Super Mario Bros 2 & 3, and Metroid working.
SMB2 will load the to title screen but when I press start the screen turns black and the audio still plays.
SMB3 loads a grey screen and locks up.
Metroid loads the title screen but when I press start the screen is a mess of broken titles.