I installed the MightyCore hardware core using the Arduino board manager. The Mendel 90 Z homing switch is at the top of the machine. This Z_HOME_POS need to be set to the distance between the top homing switch and the bed. In nophead code this value is defined as the Z_HEIGHT_MM value. I used this same variable name to match his code. To figure out this value out, I lowered the nozzle manually tby scooter_seh - Mendel90
When I was upgrading my Mendel 90 dibond to an E3Dv6 hotend, I forked Marlin 1.1.x and made all of nophead's changes to it. I added the code for the J-Head and Mendel90 bed thermistors for people to use the code on a "standard" Mendel 90 by only changing the Z_HEIGHT_MM, TEMP_SENSOR_0 and the default PID settings. I have a homemade I2C LCD Screen that requires me to change to the PANELOLU2 settinby scooter_seh - Mendel90