URGENT - Satnav hangs after USB Connection - HELP

[theFlash]

Just about to go on a long journey, decided to connect a USB drive with mp3 on it to connected of the SD Navigation Infosystem (for the first time). Display hung. Removed usb drive. Now the unit is unresponsive. Occassionally the touch screen works, momentarily.

Is there a way to reboot it? Tried disconnecting negative terminal of battery for few seconds, but no change.

Is there a reboot sequence of some sort?

Car is an early 2015 Jazz UK Model.
This is the center unit:
https://www.honda.co.uk/content/dam/local/uk/cars/owners/Car%20Owners/manuals/EN-SD-owner-manual-119391.pdf

[MiniNinjaRob]

Try removing the fuse for a couple of minutes? Probably same effect as disconnecting the battery but might be worth a try.

Also did you have files on the USB drive which the sat nav might think are update files? Shot in the dark but there was obviously something about the USB drive that the system didn’t like.