From 8fada1ebfef129ef561142eac84f3ac11fe7276e Mon Sep 17 00:00:00 2001
From: Mathias Beaulieu-Duncan <mathias@openharbor.io>
Date: Mon, 25 May 2026 20:04:17 -0400
Subject: [PATCH] patches: restore 0006 grub EFI-at-/boot fallback for
 BOOT-less SBC Upgrade
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This patch file mirrors a commit that already existed in checkouts/talos
(`a50511de7` — "grub: EFI-at-/boot fallback for BOOT-less SBC layout in
Upgrade path") but was never landed back into patches/siderolabs/talos/.
Extracted with `git format-patch` from the checkout so subsequent
`make patches` runs reproduce the same tree on a fresh clone.

Complements 0005 by handling the Upgrade code-path (in addition to the
fresh-install code-path 0005 already covers) for SBC layouts that don't
have a separate BOOT partition.
---
 ...-fallback-for-BOOT-less-SBC-layout-i.patch | 92 +++++++++++++++++++
 1 file changed, 92 insertions(+)
 create mode 100644 patches/siderolabs/talos/0006-grub-EFI-at-boot-fallback-for-BOOT-less-SBC-layout-i.patch

diff --git a/patches/siderolabs/talos/0006-grub-EFI-at-boot-fallback-for-BOOT-less-SBC-layout-i.patch b/patches/siderolabs/talos/0006-grub-EFI-at-boot-fallback-for-BOOT-less-SBC-layout-i.patch
new file mode 100644
index 0000000..9fbc2ff
--- /dev/null
+++ b/patches/siderolabs/talos/0006-grub-EFI-at-boot-fallback-for-BOOT-less-SBC-layout-i.patch
@@ -0,0 +1,92 @@
+From a50511de74db08a0b4426be88bb52ce860a008a4 Mon Sep 17 00:00:00 2001
+From: builder <build@svrnty.io>
+Date: Fri, 22 May 2026 16:10:42 -0400
+Subject: [PATCH] grub: EFI-at-/boot fallback for BOOT-less SBC layout in
+ Upgrade path
+
+---
+ .../v1alpha1/bootloader/grub/upgrade.go       | 43 +++++++++++++++----
+ 1 file changed, 35 insertions(+), 8 deletions(-)
+
+diff --git a/internal/app/machined/pkg/runtime/v1alpha1/bootloader/grub/upgrade.go b/internal/app/machined/pkg/runtime/v1alpha1/bootloader/grub/upgrade.go
+index 9e3f86b84..e99bf2939 100644
+--- a/internal/app/machined/pkg/runtime/v1alpha1/bootloader/grub/upgrade.go
++++ b/internal/app/machined/pkg/runtime/v1alpha1/bootloader/grub/upgrade.go
+@@ -6,6 +6,7 @@ package grub
+ 
+ import (
+ 	"context"
++	"fmt"
+ 	"path/filepath"
+ 
+ 	"github.com/siderolabs/go-blockdevice/v2/blkid"
+@@ -18,12 +19,12 @@ import (
+ 
+ // Upgrade copies new boot assets and updates grub configuration on an existing installation.
+ func (c *Config) Upgrade(opts options.InstallOptions) (*options.InstallResult, error) {
+-	mountSpecs := []mount.Spec{
+-		{
+-			PartitionLabel: constants.BootPartitionLabel,
+-			FilesystemType: partition.FilesystemTypeXFS,
+-			MountTarget:    filepath.Join(opts.MountPrefix, constants.BootMountPoint),
+-		},
++	var mountSpecs []mount.Spec
++
++	bootMountSpec := mount.Spec{
++		PartitionLabel: constants.BootPartitionLabel,
++		FilesystemType: partition.FilesystemTypeXFS,
++		MountTarget:    filepath.Join(opts.MountPrefix, constants.BootMountPoint),
+ 	}
+ 
+ 	efiMountSpec := mount.Spec{
+@@ -32,6 +33,23 @@ func (c *Config) Upgrade(opts options.InstallOptions) (*options.InstallResult, e
+ 		MountTarget:    filepath.Join(opts.MountPrefix, constants.EFIMountPoint),
+ 	}
+ 
++	// check if the BOOT partition is present (absent on SBC layouts like RPi5/CM5)
++	if err := mount.PartitionOp(
++		opts.BootDisk,
++		[]mount.Spec{bootMountSpec},
++		func() error {
++			return nil
++		},
++		[]blkid.ProbeOption{
++			blkid.WithSkipLocking(true),
++		},
++		nil,
++		nil,
++		opts.BlkidInfo,
++	); err == nil {
++		mountSpecs = append(mountSpecs, bootMountSpec)
++	}
++
+ 	var efiFound bool
+ 
+ 	// check if the EFI partition is present
+@@ -49,12 +67,21 @@ func (c *Config) Upgrade(opts options.InstallOptions) (*options.InstallResult, e
+ 		opts.BlkidInfo,
+ 	); err == nil {
+ 		efiFound = true
+-	}
+ 
+-	if efiFound {
++		if len(mountSpecs) == 0 {
++			// No BOOT partition (SBC layout): mount EFI at /boot so GRUB
++			// can find kernel/initramfs/grub.cfg in the expected place.
++			efiMountSpec.MountTarget = filepath.Join(opts.MountPrefix, constants.BootMountPoint)
++			c.bootFromEFI = true
++		}
++
+ 		mountSpecs = append(mountSpecs, efiMountSpec)
+ 	}
+ 
++	if len(mountSpecs) == 0 {
++		return nil, fmt.Errorf("neither BOOT nor EFI partition found on disk %s", opts.BootDisk)
++	}
++
+ 	err := mount.PartitionOp(
+ 		opts.BootDisk,
+ 		mountSpecs,
+-- 
+2.50.1 (Apple Git-155)
+