I think I have your HU's bigger brother, the DNX8160DABS. I had a similar issue occur with my old Kenwood HU (DNX7330BT), but only to the SatNav software. I had followed the instructions to the letter whilst upgrading the firmware and the satnav went into a weird gray screen with random characters on the screen. Nothing I tried worked, so in the end it had to be repaired under warranty (but not before the Service Department tried very hard to get me to pay for it).
As to your isssue, If you haven't recently downloaded a new firmware update, it's either going to be something simple like a default setting which has been inadvertently moved, or a fault with the unit. First up I'd suggest pulling out the manual and runing through any trouble-shooting steps. If that doesn't work & your unit is still under warranty, I'd suggest bringing your car into the car audio store where you bought it and seeing if their expert can diagnose the issue. If it's something simple, they should fix it gratus. And if it turns out to be a fault with the unit, atleast you're covered. Good luck!
As to your isssue, If you haven't recently downloaded a new firmware update, it's either going to be something simple like a default setting which has been inadvertently moved, or a fault with the unit. First up I'd suggest pulling out the manual and runing through any trouble-shooting steps. If that doesn't work & your unit is still under warranty, I'd suggest bringing your car into the car audio store where you bought it and seeing if their expert can diagnose the issue. If it's something simple, they should fix it gratus. And if it turns out to be a fault with the unit, atleast you're covered. Good luck!