Searching for service, result of this component missing?

Hey everyone,

I was fixing a phone, one of many I have done. I put the phone completely back together and everything was working until I noticed it had been searching for servie with and without a SIM card. I tried resetting and the date/time error trick. None of these work.

The phone has working wifi and bluetooth but there is no information on modem firmware.

I took phone back apart and noticed there was a black little square missing. Took forever to notice comparing back and forth from another 4s board but I have found it. Would this result in searching? Please help identify this component.