Jailbroken iPhone 3GS Stuck on Searching or No Service on iOS 5.1.1
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TheOperator • November 5, 2012 at 11:32am
My jailbroken iPhone 3GS running iOS 5.1.1 is stuck on Searching and eventually switches to No Service, even though I am using a known good SIM card. I am using modem firmware 05.16.05. I have heard that certain jailbreaks or baseband versions can cause signal issues on devices manufactured after a certain date. Is there a way to fix the signal on this specific firmware version?
Answers
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iClarified • January 12, 2026 at 3:37am
The issue is caused by modem firmware 05.16.05 which is not compatible with software unlocks like Ultrasn0w. To fix the Searching status and get a signal, you generally need to downgrade the baseband to version 05.13.04. 1. Check your serial number before proceeding. If the third, fourth, and fifth digits of your serial number are 134 or higher (e.g., XX135...), do not attempt a baseband modification or you will permanently damage the cellular radio. 2. If your device is older than week 34 of 2011, you can use Redsn0w to install the 06.15.00 iPad baseband. 3. After that, use Redsn0w again to downgrade from 06.15.00 to 05.13.04. 4. Once you are on baseband 05.13.04, you can install Ultrasn0w from Cydia to unlock the device and restore cellular service.
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Addles • November 11, 2012 at 10:47pm
You may need to use a custom firmware to prevent baseband updates. Take a look at this tutorial for more information: iclarified.com/25144/how-to-upgrade-your-iphone-4-3gs-without-updating-the-baseband-windows. If your phone was built after late 2011, you cannot safely modify the firmware in this way. You can check your production date via a serial checker like sndeep.info/en
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Addles • November 11, 2012 at 10:49pm
To fix the signal issue on a 3GS with that baseband, you will likely need to perform a baseband downgrade. This tutorial explains the process: www.iclarified.com/22652/how-to-downgrade-your-iphone-3gs-3g-baseband-for-unlock-windows