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That is a springboard crash issue (springboard is the home screen or desktop of device). Apple just released a new patch/update recently in iOS 11.2.
Unlock the device, then swipe up immediately from bottom of screen (before it crashes, so you have a few seconds) and enable Airplane mode (tap Airplane button) or quickly enable Airplane mode from Settings. Then go to Settings > General > Date and Time. Set the data back to 30 Nov 2017 (turn off Automatic date)
Then go to Settings > Notifications and temporarily turn off Notifications (tap Show Previews and set to Never). Now, go to Settings and disable Airplane mode.
Then connect it to WiFi, go to Settings > General > Software Update and do the update. After updating, you can set the correct date and turn Notifications back on.
If it is still not allowing you to update from there, then you need to do it from your computer. I will send the instructions. So please try the above steps first and let me know.
Please let me know if that didn't work, so I will continue to help you until we fix the problem. I will be waiting for your reply
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