Hi,
   I had upgrade my visual micro plugin for VS2017 and since the build-in serial programmer no longer work, here is the log data

esptool.py v2.8
Serial port COM4
___
Traceback (most recent call last):
  File "C:\Users\Sylvain s/upload.py", line 69, in <module>
    esptool.main(cmdline)
  File "C:/Users/Sylvain s/esptool\esptool.py", line 2890, in main
    esp.connect(args.before)
  File "C:/Users/Sylvain s/esptool\esptool.py", line 483, in connect
    raise FatalError('Failed to connect to %s: %s' % (self.CHIP_NAME, last_error))
esptool.FatalError: Failed to connect to ESP8266: Timed out waiting for packet header
The uploader process failed

Thanks for your time
Sylvain Bissonnette

It's look to work

Sketch uses 257048 bytes (26%) of program storage space. Maximum is 958448 bytes.
Global variables use 27612 bytes (33%) of dynamic memory, leaving 54308 bytes for local variables. Maximum is 81920 bytes.
C:\Users\Sylvain ython3 C:\Users\Sylvain s/upload.py --chip esp8266 --port COM4 --baud 115200 --before default_reset --after hard_reset C:\Users\SYLVAI~1\AppData\Local\Temp\arduino_build_50264/sketch_dec30a.ino.bin
esptool.py v2.8
Serial port COM4
Connecting....
Chip is ESP8266EX
Features: WiFi
Crystal is 26MHz
MAC: 84:f3:eb:41:6d:69
Uploading stub...
Running stub...
Stub running...
Configuring flash size...
Auto-detected Flash size: 1MB
Compressed 261200 bytes to 190782...

Writing at 0x00000000... (8 %)
Writing at 0x00004000... (16 %)
Writing at 0x00008000... (25 %)
Writing at 0x0000c000... (33 %)
Writing at 0x00010000... (41 %)
Writing at 0x00014000... (50 %)Invalid library found in C:\Users\Sylvain Bissonnette\Documents\Arduino\libraries\Arduino-master: no headers files (.h) found in C:\Users\Sylvain Bissonnette\Documents\Arduino\libraries\Arduino-master

Writing at 0x00018000... (58 %)
Writing at 0x0001c000... (66 %)
Writing at 0x00020000... (75 %)
Writing at 0x00024000... (83 %)
Writing at 0x00028000... (91 %)
Writing at 0x0002c000... (100 %)
Wrote 261200 bytes (190782 compressed) at 0x00000000 in 17.0 seconds (effective 123.2 kbit/s)...
Hash of data verified.

Leaving...
Hard resetting via RTS pin...
Invalid library found in C:\Users\Sylvain Bissonnette\Documents\Arduino\libraries\Arduino-master: no headers files (.h) found in C:\Users\Sylvain Bissonnette\Documents\Arduino\libraries\Arduino-master
Invalid library found in C:\Users\Sylvain Bissonnette\Documents\Arduino\libraries\Arduino-master: no headers files (.h) found in C:\Users\Sylvain Bissonnette\Documents\Arduino\libraries\Arduino-master
Invalid library found in C:\Users\Sylvain Bissonnette\Documents\Arduino\libraries\Arduino-master: no headers files (.h) found in C:\Users\Sylvain Bissonnette\Documents\Arduino\libraries\Arduino-master
Invalid library found in C:\Users\Sylvain Bissonnette\Documents\Arduino\libraries\Arduino-master: no headers files (.h) found in C:\Users\Sylvain Bissonnette\Documents\Arduino\libraries\Arduino-master
 

I found something,

The generated line from vm is
C:\Users\Sylvain ython3 "C:\Users\Sylvain s/upload.py" --chip esp8266 --port "COM4" --baud "921600" --before no_reset --after soft_reset "C:\Data\_BUILD~1\Labo\WIFIDI~1\ESP826~1\Release/WifiDimmer.ino.bin" 

And the one I just found to make it manualy work is
ost1/python3 1/tools/upload.py --chip esp8266 --port COM4 --baud 921600 --before default_reset --after hard_reset C:\Users\SYLVAI~1\OneDrive\Data\Wifi_Dimmer\Code 2.5.2\WifiDimmer\Release\wifidimmer.bin

It's look to be in the reset flags vm put --before no_reset --after soft_reset
and it's work with --before default_reset --after hard_reset 

Thanks
Sylvain Bissonnette

Great, well done and thanks for the update.