Tronxy X5S Marlin 1.1.9

The original display works, selection knob runs smoothly (menu down clockwise, enable REVERSE_MENU_DIRECTION if you'll want the original feel).

AutoTemp disabled but Filament Change is enabled (under the Tune menu)

The Filament Change procedure Configuration_adv.h:

PAUSE_PARK_RETRACT_LENGTH 6 // 2(mm) Initial retract.
avoid the blob

FILAMENT_CHANGE_UNLOAD_LENGTH 850
The filament should stop a few cm before exiting the feeder. The value depends on the length of the tube

FILAMENT_CHANGE_FAST_LOAD_LENGTH 800
The new filament is fed quickly near the nozzle, see above

ADVANCED_PAUSE_PURGE_FEEDRATE 3
The remaining fed is done slowly to clean nozzle.

ADVANCED_PAUSE_PURGE_LENGTH 100

If the extrude won't come clean increase the value. (Press the button to proceed printing quicker)

NOTE: Compile with Arduino 1.8.5 !!
Sketch uses 129196 bytes (99%) of program storage space. Maximum is 130048 bytes.

(Arduino 1.8.7 compiling consumes 130064 bytes and there for doesn't fit in)