Installer and live images have a 'basic graphics' boot menu option which uses the vesa driver and disables KMS; the release criteria specify that this must work - "The graphical boot menu for all installation images should include an entry which causes both installation and the installed system to use a generic, highly compatible video driver (such as 'vesa'). This mechanism should work correctly, launching the installer and attempting to use the generic driver" - but we currently have no test case in the release validation matrix to verify this. A test case should be written and added to the matrices. Assigning to myself for now, but if anyone else feels like contributing this, please do!