mk5bass

i bought a cheap cable off amazon it had the advance app mode button but when i pressed it no video just a black screen so i bought the expensive one from pioneer and now the advanced app mode button is not there i have the rgb input set to iphone as far as i know all settings are correct just the buttons not there? please help i really want app mode only reason i got it i thought this would be plug and play using a non jailbroken 4s thanks in advance for any help