Step 1: Open Cydia on your iPhone 4 or 3GS
Step 2: Go to Manage->Sources
Step 3: Now tap on â€œEditâ€, then tap on â€œAddâ€
Enter the following repo
Now tap on â€œAdd Sourceâ€
Step 4: Tap on Done.
Step 5: Tap on Pushfix.info and install
Step 6: After the installation Go to Pushfix.info again. Now scroll down and look for â€œUltrasn0w fixer for 4.3.1â€ Tap on it. Install the package. It will ask you to reboot your device.