I'd just like to emphasize that, although a change to always install the linux-signed kernel on AMD64 systems is necessary to fix this bug, it's not sufficient to fix the bug. As noted in my comment #25 (and elsewhere), another change is also required -- either a change to Shim or GRUB (I don't know which) or a change to how MAAS handles the boot process (to have the PXE-booted GRUB read the configuration file from the hard disk rather than chainload to GRUB on the hard disk; or perhaps a change to the way the handoff is done, if some tweak could bypass the bug).
As before, I remain able and willing to test potential fixes.
I'd just like to emphasize that, although a change to always install the linux-signed kernel on AMD64 systems is necessary to fix this bug, it's not sufficient to fix the bug. As noted in my comment #25 (and elsewhere), another change is also required -- either a change to Shim or GRUB (I don't know which) or a change to how MAAS handles the boot process (to have the PXE-booted GRUB read the configuration file from the hard disk rather than chainload to GRUB on the hard disk; or perhaps a change to the way the handoff is done, if some tweak could bypass the bug).
As before, I remain able and willing to test potential fixes.