In both an arm64 VM and an x86 VM, each with SecureBoot active, I did the following:
With only a kernel installed that was signed by the old key, I installed shim-signed from -proposed and verified that the shim alternative was set to the "previous" version. I then installed a new kernel from -proposed, signed by the new key, and verified that the shim alternative remained set to the "previous" version. I think rebooted, and ran 'sudo dpkg-reconfigure shim-signed', and verified that the alternative was now set to the "latest" shim version. I then rebooted once more to make sure I could boot through the new shim.
= kinetic verification =
shim-signed 1.54+15.7-0ubuntu1
In both an arm64 VM and an x86 VM, each with SecureBoot active, I did the following:
With only a kernel installed that was signed by the old key, I installed shim-signed from -proposed and verified that the shim alternative was set to the "previous" version. I then installed a new kernel from -proposed, signed by the new key, and verified that the shim alternative remained set to the "previous" version. I think rebooted, and ran 'sudo dpkg-reconfigure shim-signed', and verified that the alternative was now set to the "latest" shim version. I then rebooted once more to make sure I could boot through the new shim.
= jammy verification = 15.7-0ubuntu1
shim-signed 1.51.3+
same steps as kinetic
= focal verification = 15.7-0ubuntu1
shim-signed: 1.40.9+
same steps as kinetic
= bionic verification = 04.13+15. 7-0ubuntu1
shim-signed 1.37~18.
same steps as kinetic for amd64, which passed. However, I hit an issue on arm64 - bug 2004437 - so I'm unable to complete verification for that.