Printrun cannot communicate with Creality CR-100

[psl]

Ubuntu 18.04.4 amd64
printrun 1.6

Creality mini printer CR-100 has bad issues with USB communication, many issues. It is not possible to print over USB, if print even starts, it fails before the first layer is printed. I assume that source of these issues is closed source firmware in the printer. Printer has control board based on STM32F103 MPU. The board is not documented and it looks like it was designed specially for this printer.

I see one problem in pronterface 1.6 (and this is a bug in printrun, parsing of input is not well done), communication debug mode is active. Move head in Z direction (or any other direction):

SENT: M105
RECV: Echo:Get Head(0) T:29.7/0.0
SENT: M105
RECV: Echo:Get Head(0) T:29.7/0.0
SENT: G91
SENT: G0 Z10 F100
SENT: G90
SENT: M114
RECV: ok
RECV: ok
RECV: ok
RECV: X:101.500000 Y:-0.500000 Z:33.000000 E:0.000000
[ERROR] Traceback (most recent call last):
  File "/usr/lib/python2.7/dist-packages/printrun/printcore.py", line 268, in _readline
    try: self.recvcb(line)
  File "/usr/lib/python2.7/dist-packages/printrun/pronterface.py", line 1815, in recvcb
    self.update_pos()
  File "/usr/lib/python2.7/dist-packages/printrun/pronterface.py", line 1771, in update_pos
    x = float(bit[1])
ValueError: could not convert string to float:

RECV: Count X: 101.499992 Y:-0.500000 Z:23.010000
RECV: ok
SENT: M105

>>> M115
SENT: M115
RECV: Firmware_Name:BiSun
RECV: Firmware_Url:https://www.cxsw3d.com
RECV: Firmware_Ver:0.1.6
RECV: Machine_Name:CR-100
RECV: Head_Count:1
RECV: ok

[psl (slansky)]

I add similar communication with "Creality Ender 3" board, just for reference.
So it looks like CR-100 sends answer for M114 command in two lines and that is problem for pronterface.

SENT: M105
RECV: ok T:-15.00 /0.00 B:-15.00 /0.00 @:0 B@:0
SENT: M105
RECV: ok T:-15.00 /0.00 B:-15.00 /0.00 @:0 B@:0
SENT: G91
SENT: G0 X10.0 F3000
SENT: G90
SENT: M114
RECV: ok
RECV: ok
RECV: ok
RECV: X:20.00 Y:0.00 Z:2.00 E:0.00 Count X:1600 Y:0 Z:1200
RECV: ok
SENT: M105
RECV: ok T:-15.00 /0.00 B:-15.00 /0.00 @:0 B@:0
SENT: M105
RECV: ok T:-15.00 /0.00 B:-15.00 /0.00 @:0 B@:0

>>> M115
SENDING:M115
FIRMWARE_NAME:Marlin bugfix-1.1.x (Github) SOURCE_CODE_URL:https://github.com/MarlinFirmware/Marlin PROTOCOL_VERSION:1.0 MACHINE_TYPE:Ender-3 EXTRUDER_COUNT:1 UUID:cede2a2f-41a2-4748-9b12-c55c62f367ff
Cap:SERIAL_XON_XOFF:0
Cap:EEPROM:1