I had this problem as well with my iPad 2 . After many sleepless night i finally found out it was the lcd power connector switch. Turn off the iPad and make sure the charging cable is not connected. Disconnect the lcd power connector switch straight from the logic board and reconnect the charging cable to trigger the iPad to turn , if it boots up then my friend you have the same problem i had. Replace the switch and you should be all good. I apologize ahead of time if this does not help you but i thought i would share my experience with 430 nand error.