Some users faced a problem onand after .1, the problem was No service after ultrasn0w 1.2 baseband 06.15.00. Now you can fix this problem by following the below steps.
Step 1: Download
Step 2: Follow the guide posted here, but be sure to choose "install cydia" and " baseband"
Step 3: Open and install ultrasn0w 1.2 (for more details how to install ultrasn0w 1.2 Click here)
Step 4: Open Cydiia > Sources then add this link http://djayb6.com and install ultrasn0w fix.
Step 5: Restart your device .. Enjoy!