To place the Nocturn Keyboard into receive mode please press and hold buttons 1, 2 and 3 and switch the keyboard on.
You should see button 1 flash to show it is ready to receive the firmware.
Download the OS.Syx file from this article.
Now open Sysex Librarian or another similar software, double click on the OS.Syx and select the Nocturn Keyboard as the Destination.
If you now press play you should now see the firmware update onto the unit gradually.
If you have any problems please contact Technical Support.