On Wed, Feb 23, 2022 at 6:35 PM Kevin Kofler via devel devel@lists.fedoraproject.org wrote:
Chris Murphy wrote:
A work around is having GRUB set an NVRAM variable indicating the next boot should be Windows. That's an instruction to the firmware, so there's no intermediary, thus measured boot works. The next boot (from Windows) would boot Fedora again. GRUB can't get or set EFI variables yet. systemd-boot, meanwhile, will be supporting BootNext in their next release.
So, can we not, in GRUB, instead of chainloading the Windows bootloader, chainload a systemd-boot copy preconfigured to BootNext to Windows?
No because systemd-boot isn't signed with a Fedora Secure Boot signing key, so on systems with UEFI Secure Boot enabled, they'd fail to load systemd-boot.
But also, this isn't an upstreamable solution, so the Fedora and Red Hat bootloader teams are unlikely to support it either.