I recently got a spare iPad 4th gen. I did a DFU restore through iTunes, and then jailbroke it using socket. I found that on each reboot (regardless if the JB is enabled or not) I get a white screen saying "press home to upgrade."
If I press home it asks for my passcode, and after putting the passcode it shows a loading bar with an apple logo. When this bar completes it lets me on the home screen like normal. However this logs me out of facetime/imesssage (but not from iCloud), resets volume, brightness, and ringtone volume, removes widgets and causes some apps to crash until reinstalled. It's very annoying and those are the only issues I've discovered yet.
As I said, this is a recent install, so my tweak list is small. The only other change I did was removing many languages through iCleaner. iOS 10.3.4 on 32bit devices doesn't have APFS and hence I had to make space for tweaks.
How can I get rid of this screen?
Update:
I did another DFU restore and verified first thing that I could reboot without any issue, which worked twice. I then jailbroke with socket right after, and rebooted again. The white screen was back, and it persisted even when rebooting from jailed mode, or using a different jailbreak. I'm assuming socket is culprit here since it was a brand new install (no apps, tweaks, settings, nothing).
With a single time you use it, you're stuck with the white screen until you restore. Let me know if you need more details, but I won't really be testing it no more.