Revert "Merge pull request #4119 from flatcar/chewi/edk2-202511"

[tormath1]

This reverts commit 01fcddf, reversing changes made to 85b397a.

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CI: https://jenkins.flatcar.org/job/container/job/sdk/99/cldsv/ (SDK + qemu_uefi_secure tests)

This is an attempt to solve Alpha issues we seen in the last release: flatcar/Flatcar#2096

�[2J�[001;001H�[=3h�[2J�[001;001H�[2J�[001;001H�[8;042;160t�[2J�[001;001H�[2J�[001;001H�[8;056;240t�[2J�[001;001HBdsDxe: loading Boot0002 "UEFI Misc Device" from PciRoot(0x0)/Pci(0x3,0x0)
BdsDxe: failed to load Boot0002 "UEFI Misc Device" from PciRoot(0x0)/Pci(0x3,0x0): Access Denied -- rejected probably by Secure Boot
BdsDxe: No bootable option or device was found.
BdsDxe: Press any key to enter the Boot Manager Menu.

[Copilot]

Pull request overview

This PR reverts a prior set of boot/firmware-related updates in the SDK/overlay, rolling back EDK2, shim, and GRUB patch/version metadata to earlier states.

Changes:

• Drops the edk2-bin-202605 ebuild and its distfile entries, leaving the earlier edk2-bin versions in place.
• Replaces shim-16.1 with shim-15.8-r3 and introduces shim-signed-15.8-r1 plus corresponding Manifest updates.
• Adjusts the GRUB patch set and version identifiers (including FLATCAR_VERSION/SBAT entry), and removes the related changelog update entry.

Reviewed changes

Copilot reviewed 12 out of 14 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
sdk_container/src/third_party/portage-stable/sys-firmware/edk2-bin/Manifest	Removes distfile entries for edk2-202605 xpak artifacts.
sdk_container/src/third_party/portage-stable/sys-firmware/edk2-bin/edk2-bin-202605.ebuild	Deletes the edk2-bin 202605 ebuild version.
sdk_container/src/third_party/coreos-overlay/sys-boot/shim/shim-16.1.ebuild	Deletes the shim 16.1 ebuild version.
sdk_container/src/third_party/coreos-overlay/sys-boot/shim/shim-15.8-r3.ebuild	Reintroduces shim 15.8-r3 ebuild logic and dependencies.
sdk_container/src/third_party/coreos-overlay/sys-boot/shim/Manifest	Switches shim distfile reference back to shim-15.8.tar.bz2.
sdk_container/src/third_party/coreos-overlay/sys-boot/shim-signed/shim-signed-15.8-r1.ebuild	Adds a new ebuild to install pre-signed shim binaries per-arch.
sdk_container/src/third_party/coreos-overlay/sys-boot/shim-signed/Manifest	Updates signed shim distfile entries to 15.8-r1 artifacts.
sdk_container/src/third_party/coreos-overlay/profiles/coreos/targets/sdk/package.use	Modifies SDK target USE settings (static libs and QEMU-related flags).
sdk_container/src/third_party/coreos-overlay/profiles/coreos/base/package.accept_keywords	Removes the edk2-bin keyword acceptance entry.
sdk_container/src/third_party/coreos-overlay/coreos/user-patches/sys-boot/grub/grub-2.12-revert-verifiers-efi-pages.patch	Removes a GRUB revert patch from the patch set.
sdk_container/src/third_party/coreos-overlay/coreos/user-patches/sys-boot/grub/grub-2.12-01-execute-return-code.patch	Adds a GRUB patch to fix script/return-code handling for fallback behavior.
sdk_container/src/third_party/coreos-overlay/coreos/config/env/sys-boot/grub	Rolls back Flatcar GRUB version identifiers and SBAT metadata.
changelog/updates/2026-06-23-boot-updates.md	Removes the boot-updates changelog entry.

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