How to fix device when stuck in firmware update with "Do not disconnect USB" message? I have an LG Android phone. When I turned it off last night, it turned itself back on again with the firmware update showing "Do not disconnect USB". But when I received it from my contract holders, there was no USB; so I used my regular charger. I've woken up this morning and it's still on 0% after about 10 hours. 

Can someone help or give me any tips and advice?
Try holding down the power and the volume down buttons at the same time for around 10 seconds, then the device should restart and run normally again.

I remember with a situation with my iPhone when it got frozen and I had to reboot it with the same approach. This also worked on my Android phone which was stuck on 0% firmware update.