I've just fixed my iPhone 5 (10.3.3 IOS) last night, I just forgot exactly what I've done but I used a gpp lte (no iccid updated). I saw in one discussion that it won't activate the lte sim so I have a 3g sim (expired) inserted it and a no service came out but I can open Phone & Carrier in setting. Decided to eject the 3g sim & inserted the new lte sim then after a few minutes a signal came out. Been fixing it for 2weeks, thank goodness it has been resolved already. It seems like I jump started the iP5 to work again.