SBAT Revocations: Boot Process

Since November 2022, several Linux distributions, including Ubuntu 22.04.2 and 20.04.6, have upgraded to shim 15.7, which provides a critical security update to address various vulnerabilities in the boot stack. It is important to note that this update, by default, revokes the grub,1 SBAT level utilized by older installer media, including Ubuntu 22.04.1, and other distributions such as RHEL 9.0. As a result, systems running these older installer media will cease to boot once shim 15.7 is instal...