Nozzle Heating Test Failure After Firmware Update to 6.1.2
I haven't used this printer for a while, maybe 6 months and I took the first step of updating the firmware to 5.1.2 to 6.1.2 -
After booting, the firmware seemed to have installed successfully but there was an error message prompting me to run calibration/tests before printing.
I did this, and the nozzle heating test seemed to fail - no error message but just a red X next to this part of the test. I was surprised as this had never happened before, and there were no further error messages or crash logs.
During inspection, the printer, nozzle and wires all look fine and undamaged - and the nozzle easily heats up to 200 degrees during manual temperature operation. 
I ran the test again, and it seems like the nozzle heating test consistently fails when it reaches around 130-135 degrees, and immediately starts cooling down.
I would be grateful for any advice please as I would really like to fix this issue ASAP - my initial thoughts were a faulty firmware install, but I couldn't find any way to re-install the same firmware version to verify this.