I just had success using Rockallite's steps (THANK YOU Rockallite)! It took two tries, but it worked the second time. BTW, the first time, I tried a hard power off, no success, and the second time just a regular power down, with success. Don't know if it matters...
The key steps are:
1. Log out of App Store (via Settings app)
2. Turn off Wi-Fi, and turn on Airplane Mode (VERY important!)
3. Power off the iPhone (iPad, iPod touch, etc.)
4. Power on the device, turn off Airplane Mode, turn on Wi-Fi and tap App Store, boom! The blank Update page comes back.
My note: be sure to turn Apps back on under settings...