Rispondi a: Signal drop and keeps losing service "No Service"FW was definitely not the issue. Have you ever taken the phone apart? Regardless I'm thinking that your lower antenna connector has come loose or is not fully seated. I would suggest completing STEPS 1-11 of the Logic Board Install. Sostituzione scheda logica iPhone 4 You can skip steps 6-10 and step 11 will show you the connector I'm talking about.