stuck on apple logo with loading bar

Iphone 6, replaced the screen, new battery and charge port. Charging fine everything work. Guy comes back next day its stuck on apple logo. He said he let it go completely dead then wanted to charge it back up. If i hold the power and home to restart it goes to apple logo a loading bar starts under it but only goes to less then 1/4, that goes away but still on apple logo. I connected to itunes and it tells me the sim's card is unsupported, opened in 3utools and it says the same thing. Any ideas? if i remove the sims card, itunes wants me to put it back in