Can I Update My Jailbroken iPhone?
“I Have Jailbroken My iPhone – Can I Still Update It, or am I F*cked?”
Yes, but you will need to un-Jailbreak your iPhone before updating.
How do you do this? First, back up your phone.
Then, un-Jailbreak your iPhone by going to Settings > General > Reset (all the way at the bottom).
Then, plug your iPhone into the computer and select “Check for update” in iTunes.
After the update is complete, re-Jailbreak your phone, restore your backup, and wa-lah!