Firmware bug in version 1.4

When I manually (via the printer menu) lower the Z-Axis to under 120 i get the Screen on the picture.

The Extruder 2 and the heatbed (I don’t have one installed) shows a temperature of 739°C and Extruder 1 shows 0°C.
After a reset everything works fine, but I get the same error when I repeat the step.

Was the temperature readout normal before?

Before I lowered the Z-Axis i had normal temperatures of about 20°C. After I hit the reset button everything was fine again, but I had the same error after I lowered the Z-Axis (I think it was exactly the same values).

The printer prints fine, at least small prints. I didn’t tried prints with a high over 120 yet.

Hi, i have the same effect and if i turn the weel to fast (driving with z-axis) firmware crashes and do a reset.

Elsewhere all worked fine.

I have the same bug, shows MINTEMP error when I try to lower the Z axis quickly by spinning the dial. In my case I had finished a print, the element for the head was cooling down and I went to lower the table. Only a reset cures the issue. I have to lower the Z axis slowly to prevent the error occuring. Running V1.4, dual head, no heated bed as well.

This is a known bug in Marlin. If you quickly turn the dial in the manually move Z axis menu the printer will crash. It’s there since the first ultimaker version of Marlin…

This bug has been posted on the the Marlin Github but it has not been resolved.