Hot end temprature dont match temperature on the lcd display

I have an Ender 3 Pro where the temperature of the “Hot end” does not match the indicated temperature on the LCD screen. The temperature on the hot end is about 30 degrees Celsius lower than shown. I have measured the thermistor and it works as it should, 100k at 25 degrees; it seems like the temperature curve is incorrect. I have read that this can be changed in the firmware. Does anyone know how this is done? It is an 8-bit board and firmware: 1.1.6.2