The extruder should be able to load anyway, filament or not. The only need is a hot extruder.
If you toggle it over the terminal like preheat the selected extruder and then extrude by
M83 ;relative mode
G1 E20 F200 ;extrude 20mm with 200mm/min
Does it extrude?
There were a lot of firmware problems because of too less empty space on the touchscreen.
How much empty space do you have?
May get more empty space and install firmware again?