What is the problem?
When I send a dual extrusion gcode from Octoprint, thi only uses one color, but the gcode works fine from SD card
What did you already try to solve it?
I have been reviewing this issue. My Geeetech a20m uses 16 virtual extruders in the firmware.
For my tests, I have put 2 extruders and "Shared Nozzle" in Octoprint settings. Actually, I'm not sure how many extruders I should put in the octoprint extruder number field
I'm using Cura, and I don't know if I have to add something there
This is part of the serial log;
2020-04-18 18:29:18,553 - Recv: echo:busy: processing
2020-04-18 18:29:18,568 - Recv: T:190.80 /190.00 B:60.14 /60.00 @:41 B@:71 W:0
2020-04-18 18:29:18,740 - Recv: T:190.03 /190.00 B:60.16 /60.00 @:77 B@:68
2020-04-18 18:29:19,455 - Recv: ok
2020-04-18 18:29:19,460 - Send: N27 M10518
2020-04-18 18:29:19,466 - Recv: ok T:190.48 /190.00 B:60.05 /60.00 @:60 B@:82
2020-04-18 18:29:19,479 - Send: N28 M109 T1 S19031
2020-04-18 18:29:19,493 - Recv: echo:M109 Invalid extruder 1
2020-04-18 18:29:19,494 - T1 reported as invalid, reverting to T0
2020-04-18 18:29:19,496 - Recv: ok
2020-04-18 18:29:19,499 - Not queuing T0, that tool doesn't exist according to the printer profile or was reported as invalid by the firmware
2020-04-18 18:29:19,504 - Send: N29 M82*34
2020-04-18 18:29:19,509 - Recv: ok
Logs say: "Invalid extruder 1", but when reverting to T0, logs say that the T0 doesn't exist