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How to Fix iPhone 4 No Signal After Jailbreak and Unlock?

Hello, I’ve been wondering if I could fix my jailbroken iPhone 4. My iPhone 4 is running on a jailbroken iOS 4.3.1 using PwnageTool 4.3 with Ultrasn0w carrier unlock installed. I’ve been using this iPhone 4 for months now and for some reason I have an annoying problem. I have a very low cellular signal. I jailbroke and unlock my iPhone 4 as instructed and it is activated, but I’m still having issues on my cellular signal. I don’t want to re-jailbreak and re-unlock my iPhone again on new iOS 4.3.3 because I might the ability to unlock my iPhone again. Please help.

Asked by: Owen from Albuquerque, New Mexico

Hello Owen, I’m definitely sure that you are experiencing “One Signal Bar” issue. This bug normally occurs on iPhone 4 and iPhone 3GS with old baseband and jailbroken using either PwnageTool 4.3 or Sn0wbreeze 2.5 on iOS 4.3.1. Meaning, iPhone 4 and iPhone 3GS with baseband 04.26.08 / 05.11.07 / 05.11.07 / 05.12.01 / 05.13.04 / 01.59.00 / 05.13.04 / 01.59.00 / 05.13.04 / 01.59.00 / 05.14.02 / 6.15.00 / 05.15.04 were also experiencing this bug. And iPhone and iPhone 3GS with baseband 02.10.04 / 03.10.01 / 04.10.01 / 05.16.01 / 05.16.02 are not affected with “One Signal Bar” bug. But, the good news is, you will be able to fix this bug by installing a new version of Ultrasn0w.

To fix “One Signal Bar” issue, just simply download and install Ultrasn0w 1.2.1 on your iPhone. For those who aren’t aware on how to install Ultran0w 1.2.1, all you have to do is launch Cydia app from the Springboard of your jailbroken iPhone. Now, tap on the Manage tab and on Sources section, then on Edit and Add button. Now you have to add as Cydia/APT URL and click on Add Source button. Once verified and updated, tap on Return to Cydia button at the bottom. Click on the Search tab at the bottom and type Ultrasn0w in the search field. From the result, select Ultrasn0w and install. Check your signal bar once you have downloaded and installed Ultrasn0w, if you still got “One Signal Bar” then click on Restart Springboard button or just simply reboot your iPhone.
Unlock iPhone No Signal

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    Buddhika7 years ago

    I used a IMEI unlock service to unlock my iPhone 4. After receiving conformation that it was unlocked I restored it as a new iPhone.I activated it with the new sim and it showed the “Congratulations,your iPhone is unlocked” message but I always keep getting NO SERVICE.It detects my carrier fine,but I don’t get service.Thesim works on other phones (not iPhones but other normal phones).I used to use gevey to unlock before the IMEI unlock so I think its not a hardware fault.Can someone please help me and tell me where I went wrong?

    drummer8 years, 7 months ago

    Thanks for the instructions on how to fix this. When installing ultrasn0w, is it normal to get errors towards the bottom or end of the installation? I have an iPhone 4 running IOS 6.1.2 and my carrier is C-Spire.Thanks,drummer