Update iOS on jailbroken iPhone 5S with evasi0n7 *without USB*

I jailbreaked my iPhone 5S with evasi0n7 [iOS 7.0.4] a few months ago. The thing is, that I accidently broke my USB driver on the iPhone (I can still charge the phone but not connect it to any USB data port).

I want to update my iPhone to iOS 8 and delete the Jailbreak. The problem is, that I cannot use iTunes to update, because the USB connection doesn't work. I already made a backup of all personal data using SSH/SFTP and WiFi.

Do you know how to update my iPhone to iOS8? (The problem is that evasi0n is somehow preventing the Phone to show the Update in the Settings > General-tab)

Edit: I also used Settings > General > Reset > "Erase all Content and Settings" but it just got stuck and booted up with the evasi0n7 still installed