Display NAD M33

Today i boucht a M33. I thought i had to update the firmware so i downloaded the latest firmware on the usb stick delivered with the device. I plugged it in and selected update via the usb stick. It seemed the M33 started to update as the bluesound app was showing "updating" After the reboot, the display keeps black. The device works ok and i can play music etc. When turn on the device the display lights up a a little but but nothing happens. The device works ok but menu's and albums etc are not shown. Any idea how this happened.

How can i install again manally the most recent firmware as i can't use the display anymore.

Updating via the bluesound app does not work as it shows "no update available"

All suggestions are very welcome.