iOS 11.0.3 WDT timeout

Hello,

I have an iPhone 5S which worked until a few days ago when I had the awesome idea to update to the latest firmware (11.0.3). Now, it restart every 1 minute so i cant backup, restore or do anything.

This happens when I unlock the device, if it restarts and i don't unlock the screen will stay "unrebooted".

I took it to my nearest apple store and they said that must be a software problem so I came here and ask if there is some known bug about this "rebooting problem".

Thank you.