I turned on my controller for the P4 Pro+ to discover I needed an update. I followed all the on-screen instructions and everything seemed to be running smoothly. I'm now on the Upgrade Firmware screen and it is stuck at 30%. I can't back out. It hasn't moved in over an hour. Any suggestions?

Just to clarify, were you connected to a stable internet source? Given how long you've let it sit to download, you may need to take the chance of power cycling the unit and reattempting the firmware update via the Assistant 2 software.