Newer Cura compatibility issues?

[stuartpb]

What's incompatible between these profiles and a recent build of Cura like 3.1? Is there something wrong with the start code?

[stuartpb]

So, here's an example of the beginning of gcode produced by Cura 3.1 using the gcode from here, which I'm just now realizing isn't the gcode in these profiles:

;FLAVOR:RepRap
;TIME:4556
;Filament used: 4.2266m
;Layer height: 0.2
;Generated with Cura_SteamEngine 3.1.0
T0
M190 S40
M104 S200
M104 T1 S200
M109 S200
M109 T1 S200
M82 ; absolute extrusion mode
; -- START GCODE --
M136 ; start build
M73 P0
G90 ; absolute coordinates
;
; set temperatures and assert Vref
M140 S40.0
M104 S210 T0
G130 X118 Y118 A118 B118 ; set stepper motor Vref to defaults
; let the Z stepper vref stay at eeprom level (probably 40)
;
; home and recall eeprom home position
T0 ; home on the right nozzle
G28 X Y Z ; home all axes at homing speed
G92 X0 Y0 Z0 A0 B0 ; set all coords to 0 for now
G1 Z5 F500 ; move Z 5mm away so we can carefully hit the limit switch
G161 Z F100 ; home Z slowly
M132 X Y Z ; recall stored home offsets for XYZ axes
;
; wait for heat up
G1 X110 Y-72 Z30 F3300 ; move to waiting position
M116 ; wait for temps
;
; purge and wipe
G92 E0 ; set current extruder position as 0 so that E15 below makes sense
G1 X110 Y-70 Z0.2 F2400.0 ; move to just on the bed
G1 X110 Y70 E15 F1200.000 ; extrude a line of filament along the right edge of the bed
G92 E0 ; set E to 0 again because the slicer's next extrusion is relative to this 0
;
; Sliced at: Thu 28-12-2017 01:00:00
; Basic settings: Layer height: 0.2 Walls: 0.8 Fill: {fill_density}
; Print time: 01:15:57
; Filament used: [4.23, 0.0]m [12.6060494921875, 0.0]g
; Filament cost: [0, 0]
; -- end of START GCODE --

From this, we can make a couple observations:

• Cura inserts its own heating code before the start gcode, which makes the heating section redundant (including the M116 which is redundant due to the M109 lines)
• The fill_density variable in the settings comment should be infill_sparse_density

[stuartpb]

For posterity, the start and end gcodes as defined by the profile in this repo (because it's a pain to read the raw JSON):

(@start_gcode_begin)
M73 P0 ; tell the firmware we're starting a build
G130 X118 Y118 A118 B118 ; set vref's to default_value
;
; home and set coordinates
T0 ; home on the right extruder
G90 ;  set positioning to absolute
G28 X Y Z ; home XYZ at default_value home feedrates
G92 X0 Y0 Z0 A0 B0 ; define this as Z=0, the other coords are technically unnecessary but x3g requires them so gpx will make some up
; home Z again slowly to give more consistent first layer height
G1 Z5 ; move the platform 5mm down
G28 Z F500 ; so we can home z again slowly
M132 X Y Z  ; Recall stored home offsets
;
; wait for heat up
G1 X{extruder_prime_pos_x} Y{extruder_prime_pos_y} Z{extruder_prime_pos_z} F3300 ; move to waiting position (front right corner of print bed)
M116 ; wait for target temperatures to be reached. GPX only, RepG doesn't understand
(@start_gcode_end)

(@end_gcode_begin)
M73 P100 ; end build progress
M140 S0 ; set bed temperature to 0
M104 S0 T0 ; set extruder temperature to 0
M104 S0 T1 ; set other extruder temperature to 0
T0 ; Next job may assume T0 is the current tool
G1 Z150 ; platform to the bottom
G162 X Y F2500 ; home X and Y axes
M18 ; disable all stepper motors
M70 P5 (We <3 Making Things!)
M72 P1 ; Play Ta-Da song
(@end_gcode_end)