I've an old 3gs on 5.1.1, 05.13.04.
It was unlocked using the ipad firmware long ago, but was factory reset and then updated to 5.1.1. Now it has No signal, whatever sim is inserted.
I'm not savy with iphones anymore, but would love to fix it for my mum to use. How can i get it to accept a signal, thanks for help!