I resolved my issue last night (in case anyone also has it) … when I delved deeper into my logs, I found that Pillow was trying to upgrade the bomradarloop module, and failing.
the resolution ended up being:
sudo aptitude install libtiff5-dev libjpeg8-dev zlib1g-dev libfreetype6-dev liblcms2-dev libwebp-dev libharfbuzz-dev libfribidi-dev tcl8.6-dev tk8.6-dev python-tk
then activating the python venv, and upgrading Pillow
source /srv/homeassistant/bin/activate
pip install Pillow
pip install bomradarloop
reboot, and voila - bom sensor working again