You'll need to SSH into your snakeoil PC.
Run the following:
apt install idle3-tools
then modify /etc/rc.local file:
sudo vi /etc/rc.local
and add a line (Replace X with the drive letter)
idle3ctl -d /dev/sdX
Note that your changes to rc.local may disappear on firmware updates... In the future Snakeoil will allow you run a script on start up/shutdown, but until then, keep this in mind.