V2.0 is not available in pypi yet, but you can get it on github:
https://github.com/themadinventor/esptool
Some performance numbers, writing a 432KB firmware image with the new version. If you can use a high baud rate the difference is minor, but at lower baud rates it's quite significant:
Default baud rate (115200bps):
- esptool v1.3 39.6s total, 38.6s spent flashing (92.4kbit/s)
- esptool v2.0 29.4s total, 27.5s spent flashing (effective 128.9kbit/s)
1.5megabit baud rate (-b 1500000)
- esptool v1.3 6.9s total, 5.9s spent flashing (604kbit/s)
- esptool v2.0 6.6s total, 4.6s spent flashing (755kbit/s)
Other new features that apply to ESP8266 include --before and --after options for changing the reset behaviour before and after esptool.py runs.
Please report any bugs or feature requests via the Github issues page.