The reset image they provide will not work on the board you wish to upgrade. This board did not exist nor did Roon OS support this board when they built the image and shipped the unit.
If you were to run ROCK on this, your audio support would disappear, because the NADAC+PLAYER has a custom Roon OS.
There is a way to do this, but it requires an updated Roon OS for NADAC+PLAYER. There is a plan to deploy this, but it is not out yet. Soon, but neither I nor Merging can provide you a schedule.