Knomi2 you can get stuck in the preheat screen if you set the goal temp below the ambient temp of the room

[sprior]

With the Knomi 2, if the ambient room temp is for example 19 degrees C and you swipe to the preheat screen and press the button to preheat the bed, then press the check button while the setting is above 0 but below the ambient room temp, the Knomi 2 will be stuck on the preheating screen with no way to swipe out. The only way to recover is to use some other control interface of the printer and turn the heaters off.

[sprior]

The easiest solution might be when you go to the set temp screen for preheat, instead of the default value being 0 set the default to the current temp. That way you'll never be able to set it to a temp below what the bed or hot end can reach and the preheating screen would be satisfied immediately. If you want to turn off the heater there's a cooldown button on another screen to use.

[sprior]

I believe the temp wheel actually lets you select a value below zero which is pretty silly. There should be some reasonable constraints on the values that can be selected.