Please help replaced the back on my iphone 3g have done this before and not had a problem but was a good while ago,...this time the home button no longer works...i swapped with my mums front of fone (digitalizer screen etc) and its the same with hers when i attach it to the motherboard on my phone - whats causing it ??? i believe the home button is cable 3 and im sliding it all the way in so cant figure it out