Had to pip uninstall typing in order to get past AttributeError: type object 'Callable' has no attribute '_abc_registry'. See https://community.home-assistant.io/t/upgrade-error-cryptography-module/194496.
Something else strange:
ERROR: pip's dependency resolver does not currently take into account all the packages that are installed. This behaviour is the source of the following dependency conflicts.
esphome 1.16.0 requires PyYAML==5.3.1, but you have pyyaml 5.4.1 which is incompatible.
esphome 1.16.0 requires voluptuous==0.12.0, but you have voluptuous 0.12.1 which is incompatible.
Successfully installed PyJWT-1.7.1 aiohttp-3.7.3 astral-1.10.1 async-timeout-3.0.1 attrs-19.3.0 bcrypt-3.1.7 ciso8601-2.1.3 cryptography-3.2 h11-0.12.0 homeassistant-2021.2.0 httpcore-0.12.3 httpx-0.16.1 multidict-5.1.0 pip-20.2.4 python-slugify-4.0.1 pyyaml-5.4.1 requests-2.25.1 ruamel.yaml-0.15.100 sniffio-1.2.0 text-unidecode-1.3 voluptuous-0.12.1 voluptuous-serialize-2.4.0 yarl-1.6.3
Default /home/pi/.homeassistant config. Fixed that by putting it in env folder.
Needed to install dependencies. Now following https://www.home-assistant.io/docs/installation/raspberry-pi/.
sudo apt-get install python3 python3-dev python3-venv python3-pip libffi-dev libssl-dev libjpeg-dev zlib1g-dev autoconf build-essential libopenjp2-7 libtiff5