Depending on what version your currently doing it sort of changes, but if you look in Marlin_main.cpp and search for "void gcode_G28()" That is the routine that handles homing. And if you skim through it until you see something similar to the following:
That was the section I commented out at one time from the RCBugFix-RC7 version. It was different in the RCBugFix-RC6 version, so it might not look exactly like that depending on what version your using.
There might be another location to look too, but I don't remember if it was just the one section.
if (home_all_axis || homeX || homeY) {
// Raise Z before homing any other axes and z is not already high enough (never lower z)
destination[Z_AXIS] = LOGICAL_Z_POSITION(Z_HOMING_HEIGHT);
if (destination[Z_AXIS] > current_position[Z_AXIS]) {
#if ENABLED(DEBUG_LEVELING_FEATURE)
if (DEBUGGING(LEVELING)) {
SERIAL_ECHOPAIR("Raise Z (before homing) to ", destination[Z_AXIS]);
SERIAL_EOL;
}
#endif
do_blocking_move_to_z(destination[Z_AXIS]);
}
}
That was the section I commented out at one time from the RCBugFix-RC7 version. It was different in the RCBugFix-RC6 version, so it might not look exactly like that depending on what version your using.
There might be another location to look too, but I don't remember if it was just the one section.