@Lakotaubp
Of course not - thank you - I'll try to set this as solved now

I'd like to downgrade Android 12 --> 9 for Sargo in order to install UT, but I cannot locate the appropriate Pixel factory image. I can verify the hash of the appropriate image if I were to find it elsewhere.
The instructions I started with use the factory image.

Google makes a sideload image available ("Full OTA"), but my attempt to sideload was met with failure. My phone didn't want to downgrade. Following the Google instructions for sideloading, the phone didn't want to move to a lower numbered release.

If it matters - my computer is on Ubuntu 20.04 and the platform-tools I have date back to 2008.

Any help would be appreciated.