Com error on upload

[a2retro]

I know this is most likely a local configuration issue but I cannot figure out why the pre-configured msys environment will not let me access the com port that is connected to my esp32 core dev module.

1. Shows up fine as a sillabs cp210X under device manager - COM4
2. Port accessible under windows and using putty shows preloaded boot screen
3. tried running MSYS as admin didn't help
4. Under menuconfig have device set to /dev/ttyS3 and baud set to 112500 (matches in windows com config - 112500,8,N,1)
5. Able to access the com port using minicom under MSYS

Error
File "C:/msys32/mingw32/lib/python2.7/site-packages/serial/serialwin32.py", line 62, in open
raise SerialException("could not open port {!r}: {!r}".format(self.portstr, ctypes.WinError()))
serial.serialutil.SerialException: could not open port '/??/COM4': WindowsError(3, 'The system cannot find the path specified.')
make: *** [/home/Glenn/src/esp-idf/components/esptool_py/Makefile.projbuild:28: flash] Error 1

Perhaps my module is not in the correct mode?

Edit: Figured out how to put it in download mode but python still cannot open com4

Boot screen references "Please refer to document ssc_commands.xlsx for detail"
Is that available or any other infos/pointers to already online docs about this module would be appreciated.

[a2retro]

So as Rudi suggested - just use COM4 as device name not /dev/ttyS3

No i got this issue

Flashing project app to 0x10000...python /home/Glenn/src/esp-idf/components/esptool_py/esptool/esptool.py --chip esp32 --port COM4 --baud 115200...
Reaping winning child 0x200481c8 PID 6008
Live child 0x200481c8 (flash) PID 2476
esptool.py v2.0-dev
Connecting...
Uploading stub...
Calling 4009068c
Stub running...
Attaching SPI flash...
Configuring flash size...
Erasing flash...
Took 0.02s to erase flash block
Wrote 8192 bytes at 0x00001000 in 0.7 seconds (91.2 kbit/s)...
Hash of data verified.
Erasing flash...
Took 0.00s to erase flash block
Wrote 360448 bytes at 0x00010000 in 31.8 seconds (90.6 kbit/s)...
Hash of data verified.
Erasing flash...
Took 0.00s to erase flash block
Wrote 8192 bytes at 0x00004000 in 0.7 seconds (91.2 kbit/s)...
Hash of data verified.

Leaving...

A fatal error occurred: Failed to enter RAM download mode (result was 0xff, 0x0)
Reaping losing child 0x200481c8 PID 2476
make: *** [/home/Glenn/src/esp-idf/components/esptool_py/Makefile.projbuild:28: flash] Error 2
Removing child 0x200481c8 PID 2476 from chain.

Edit: Seems like app working anyways so not sure if critical.

[ESP_Angus]

Hi a2retro,

Thanks for reporting this bug. We have a fix on its way, you can track it via this Issue on github: https://github.com/espressif/esp-idf/issues/14

In the meantime, the data is being flashed properly so you can ignore the error.