Hi Shane, just reading through this thread. My colleagues above reproduced the failure as:
[main] Reading state information...
[main] E: Unable to locate package nvidia-driver-435
You are basing your image on Ubuntu bionic, as in:
FROM balenalib/%%BALENA_MACHINE_NAME%%-ubuntu-python:3.6-bionic-build
But I don’t see the nvidia-driver-435 appearing on the bionic default feeds according to packages.ubuntu.com. It does appear both in focal or in the bionic-updates feed.
However you mention this was working for you before, so I am confused.
Regarding the io.balena.features.gpu feature, unfortunately it is currently not working, see https://github.com/balena-io/balena-supervisor/issues/1449