After 06.15.00 baseband downgrade many users receive error No Signal on iPhone 3GS or 3G so I decided to write you complete guide on how to fix No Signal on iPhone 3GS (G). Yesterday I wrote you a guide on how to downgrade 06.15.00 baseband to 05.13.04 to fix GPS and to have a possibility to unlock your iPhone using Ultrasn0w tool which is good for o5.13.04 baseband. The chance to downgrade this iPad baseband came after chance to download Redsn0w 0.9.14b1 and many iPhone users who stuck on iPad baseband started to perform this downgrade. But after downgrading process many of them received No Signal status and some other crashes after applying Ultrasn0w. Fortunately iPhone Dev team showed the way to fix No Signal on iPhone 3GS (3G) and other crashes. They advice us just to reinstall Mobile Substrate and Ultrasn0w. And here below I'll show you how to do that using Cydia package manager.

How to Reinstall Mobile Substrate and Ultrasn0w To Fix No Signal on iPhone 3GS

Step 1. The very first thing you need to do is to locate Mobile Substrate in Cydia. To do this just open Cydia => Manage => Packages.

Step 2. When you find Mobile Substrate just tap on it and then click Modify in the top right corner of this tweak. Step 3. When you click Modify you will see Reinstall, Remove and Cancel, so just pick Reinstall. Step 4. Now be attentive! Do not click Confirm, instead of this you must click Continue Queuing. Note: You need to do this because this allows you to perform more than one re-installation in the future. Step 5. Now you should to reinstall Ultrasn0w to fix No Signal on iPhone 3GS (G). So go to Cydia => Manage => Packages and find Ultrasn0w. Step 6. After finding Ultrasn0w just click Modify => Reinstall => Confirm and wait till the re-installation completes. Step 7. After Mobile Substrate and Unltrasn0w re-installation you should fix No Signal on iPhone 3GS and other crashing after 06.15.00 downgrade. Update: If you have problems with iPad baseband downgrade just use this link to fix 06.15.00 not working downgrade. That is it. Now you know how to fix No Signal error on your iPhone 3GS and iPhone 3G so share your experience of doing this using share buttons below. Also it is interesting to me personally if it works on iPhone 3G because I tried to fix No Signal on iPhone 3GS reinstalling updated Mobile Substrate and Ultrasn0w and can confirm that it works. But I can't be sure about iPhone 3G. So use comment form below to write about your results after re-installation.