[PATCH] x86_64: add systemd-boot images

Jonas Lochmann openwrt at jonaslochmann.de
Tue Dec 30 03:54:17 PST 2025


grub2 has many features, including different implementations for loading
the linux kernel. At one machine, the "linux" command cannot start
OpenWrt while the "chainloader" command for the same kernel file works.

Both commands use the same UEFI API, but the surrounding steps are
slightly different. An UEFI native bootloader seems to be similar to
"chainloader" in grub while avoiding a ton of extra features. One of
those bootloaders is systemd-boot, formerly known as gummiboot.
While it contains the name "systemd" and is part of the systemd
codebase, the resulting efi executable can be used independent of
systemd. systemd contains bootctl for managing a systemd-boot
installation, but systemd-boot uses simple text configuration files
so that this is not needed at all.

Signed-off-by: Jonas Lochmann <openwrt at jonaslochmann.de>
---
 config/Config-images.in                       | 18 ++++--
 package/boot/systemd-boot/Makefile            | 55 +++++++++++++++++++
 .../x86/base-files/lib/upgrade/platform.sh    |  1 +
 target/linux/x86/image/Makefile               | 28 ++++++++++
 target/linux/x86/image/systemdboot-entry.cfg  |  4 ++
 .../linux/x86/image/systemdboot-loader.conf   |  1 +
 6 files changed, 101 insertions(+), 6 deletions(-)
 create mode 100644 package/boot/systemd-boot/Makefile
 create mode 100644 target/linux/x86/image/systemdboot-entry.cfg
 create mode 100644 target/linux/x86/image/systemdboot-loader.conf

diff --git a/config/Config-images.in b/config/Config-images.in
index fcc5fa52cb..ff93990834 100644
--- a/config/Config-images.in
+++ b/config/Config-images.in
@@ -229,6 +229,12 @@ menu "Target Images"
 			prompt "journal size" if TARGET_ROOTFS_UBIFS
 			default ""
 
+	config SYSTEMDBOOT_IMAGES
+		bool "Build systemd-boot images (EFI x86_64 targets only)"
+		depends on TARGET_x86_64
+		depends on TARGET_ROOTFS_EXT4FS || TARGET_ROOTFS_JFFS2 || TARGET_ROOTFS_SQUASHFS || TARGET_ROOTFS_EROFS
+		select PACKAGE_systemd-boot
+
 	config GRUB_IMAGES
 		bool "Build GRUB images (Linux x86 or x86_64 host only)"
 		depends on TARGET_x86
@@ -251,23 +257,23 @@ menu "Target Images"
 
 	config GRUB_CONSOLE
 		bool "Use Console Terminal (in addition to Serial)"
-		depends on GRUB_IMAGES || GRUB_EFI_IMAGES
+		depends on GRUB_IMAGES || GRUB_EFI_IMAGES || SYSTEMDBOOT_IMAGES
 		default y
 
 	config GRUB_BAUDRATE
 		int "Serial port baud rate"
-		depends on GRUB_IMAGES || GRUB_EFI_IMAGES
+		depends on GRUB_IMAGES || GRUB_EFI_IMAGES || SYSTEMDBOOT_IMAGES
 		default 38400 if TARGET_x86_generic
 		default 115200
 
 	config GRUB_FLOWCONTROL
 		bool "Use RTE/CTS on serial console"
-		depends on GRUB_IMAGES || GRUB_EFI_IMAGES
+		depends on GRUB_IMAGES || GRUB_EFI_IMAGES || SYSTEMDBOOT_IMAGES
 		depends on TARGET_SERIAL != ""
 
 	config GRUB_BOOTOPTS
 		string "Extra kernel boot options"
-		depends on GRUB_IMAGES || GRUB_EFI_IMAGES
+		depends on GRUB_IMAGES || GRUB_EFI_IMAGES || SYSTEMDBOOT_IMAGES
 		help
 		  If you don't know, just leave it blank.
 
@@ -279,8 +285,8 @@ menu "Target Images"
 		  If you don't know, 5 seconds is a reasonable default.
 
 	config GRUB_TITLE
-		string "Title for the menu entry in GRUB"
-		depends on GRUB_IMAGES || GRUB_EFI_IMAGES
+		string "Title for the menu entry in GRUB and systemd-boot"
+		depends on GRUB_IMAGES || GRUB_EFI_IMAGES || SYSTEMDBOOT_IMAGES
 		default "OpenWrt"
 		help
 		  This is the title of the GRUB menu entry.
diff --git a/package/boot/systemd-boot/Makefile b/package/boot/systemd-boot/Makefile
new file mode 100644
index 0000000000..425f53561d
--- /dev/null
+++ b/package/boot/systemd-boot/Makefile
@@ -0,0 +1,55 @@
+#
+# This is free software, licensed under the GNU General Public License v2.
+# See /LICENSE for more information.
+#
+
+include $(TOPDIR)/rules.mk
+
+PKG_NAME:=systemd-boot
+PKG_VERSION:=259
+PKG_RELEASE:=1
+
+PKG_SOURCE_PROTO:=git
+PKG_SOURCE_URL:=https://github.com/systemd/systemd.git
+PKG_MIRROR_HASH:=1671487dc511d60d3c50070e8f5c6dec228a1d97cdedd7f5508a966bb06ba614
+PKG_SOURCE_DATE:=2025-12-17
+PKG_SOURCE_VERSION:=9ca433482f2281d71718718705ca8cd3bf562ad6
+PKG_CPE_ID:=cpe:/a:systemd_project:systemd:259:-
+
+PKG_LICENSE:=LGPL-2.1-or-later
+PKG_LICENSE_FILES:=LICENSES/README.md
+PKG_BUILD_DEPENDS:=python-pyelftools/host python-jinja2/host gperf/host
+PKG_INSTALL:=1
+
+MESON_USE_STAGING_PYTHON:=1
+
+include $(INCLUDE_DIR)/package.mk
+include $(INCLUDE_DIR)/meson.mk
+
+define Package/systemd-boot
+  SECTION:=boot
+  CATEGORY:=Boot Loaders
+  TITLE:=Simple UEFI boot manager
+  DEPENDS:=@TARGET_x86_64 +libblkid
+  URL:=https://github.com/systemd/systemd/tree/main/src/boot
+endef
+
+define Package/systemd-boot/description
+  systemd-boot Simple UEFI boot manager
+
+  systemd-boot executes EFI images. The default entry is selected by a configured
+  pattern (glob) or an on-screen menu.
+endef
+
+MESON_ARGS += \
+	-Dmode=release \
+	-Dlibc=musl \
+	-Dbootloader=enabled \
+	--auto-features=disabled
+
+define Package/systemd-boot/install
+	$(INSTALL_DIR) $(1)/usr/sbin $(1)/usr/lib/systemd-boot
+	$(INSTALL_DATA) $(PKG_INSTALL_DIR)/usr/lib/systemd/boot/efi/systemd-bootx64.efi $(1)/usr/lib/systemd-boot/
+endef
+
+$(eval $(call BuildPackage,systemd-boot))
diff --git a/target/linux/x86/base-files/lib/upgrade/platform.sh b/target/linux/x86/base-files/lib/upgrade/platform.sh
index 5dad7a538a..bca3d0426f 100644
--- a/target/linux/x86/base-files/lib/upgrade/platform.sh
+++ b/target/linux/x86/base-files/lib/upgrade/platform.sh
@@ -125,6 +125,7 @@ platform_do_upgrade() {
 		mount -t $parttype -o rw,noatime "/dev/$partdev" /mnt
 		set -- $(dd if="/dev/$diskdev" bs=1 skip=1168 count=16 2>/dev/null | hexdump -v -e '8/1 "%02x "" "2/1 "%02x""-"6/1 "%02x"')
 		sed -i "s/\(PARTUUID=\)[a-f0-9-]\+/\1$4$3$2$1-$6$5-$8$7-$9/ig" /mnt/boot/grub/grub.cfg
+		sed -i "s/\(PARTUUID=\)[a-f0-9-]\+/\1$4$3$2$1-$6$5-$8$7-$9/ig" /mnt/loader/entries/main.conf
 		umount /mnt
 	fi
 }
diff --git a/target/linux/x86/image/Makefile b/target/linux/x86/image/Makefile
index 29bebeb748..6f11712e87 100644
--- a/target/linux/x86/image/Makefile
+++ b/target/linux/x86/image/Makefile
@@ -52,6 +52,30 @@ define Build/combined
 		256
 endef
 
+define Build/systemd-boot
+	rm -fR $@.boot
+	$(INSTALL_DIR) $@.boot/boot $@.boot/efi/boot $@.boot/loader/entries
+
+	$(CP) $(KDIR)/$(KERNEL_NAME) $@.boot/boot/vmlinuz
+	-$(CP) $(STAGING_DIR_ROOT)/boot/. $@.boot/boot/
+	$(CP) $(STAGING_DIR_ROOT)/usr/lib/systemd-boot/systemd-bootx64.efi $@.boot/efi/boot/bootx64.efi
+
+	sed \
+		-e 's#@GPT_ROOTPART@#root=$(GPT_ROOTPART) rootwait#g' \
+		-e 's#@CMDLINE@#$(BOOTOPTS) $(GRUB_CONSOLE_CMDLINE)#g' \
+		-e 's#@TITLE@#$(GRUB_TITLE)#g' \
+		./systemdboot-entry.cfg > $@.boot/loader/entries/main.conf
+
+	$(CP) ./systemdboot-loader.conf $@.boot/loader/loader.conf
+
+	PADDING="1" SIGNATURE="$(IMG_PART_SIGNATURE)" \
+		GUID="$(IMG_PART_DISKGUID)" $(SCRIPT_DIR)/gen_image_generic.sh \
+		$@ \
+		$(CONFIG_TARGET_KERNEL_PARTSIZE) $@.boot \
+		$(CONFIG_TARGET_ROOTFS_PARTSIZE) $(IMAGE_ROOTFS) \
+		256
+endef
+
 define Build/grub-config
 	rm -fR $@.boot
 	$(INSTALL_DIR) $@.boot/boot/grub
@@ -114,14 +138,18 @@ define Device/Default
   IMAGE/combined-efi.vdi := grub-config efi | combined efi | grub-install efi | qemu-image vdi
   IMAGE/combined-efi.vmdk := grub-config efi | combined efi | grub-install efi | qemu-image vmdk
   IMAGE/combined-efi.vhdx := grub-config efi | combined efi | grub-install efi | qemu-image vhdx -o subformat=dynamic
+  IMAGE/systemd-boot.img := systemd-boot | append-metadata
+  IMAGE/systemd-boot.img.gz := systemd-boot | gzip | append-metadata
   ifeq ($(CONFIG_TARGET_IMAGES_GZIP),y)
     IMAGES-y := rootfs.img.gz
     IMAGES-$$(CONFIG_GRUB_IMAGES) += combined.img.gz
     IMAGES-$$(CONFIG_GRUB_EFI_IMAGES) += combined-efi.img.gz
+    IMAGES-$$(CONFIG_SYSTEMDBOOT_IMAGES) += systemd-boot.img.gz
   else
     IMAGES-y := rootfs.img
     IMAGES-$$(CONFIG_GRUB_IMAGES) += combined.img
     IMAGES-$$(CONFIG_GRUB_EFI_IMAGES) += combined-efi.img
+    IMAGES-$$(CONFIG_SYSTEMDBOOT_IMAGES) += systemd-boot.img
   endif
   KERNEL := kernel-bin
   KERNEL_INSTALL := 1
diff --git a/target/linux/x86/image/systemdboot-entry.cfg b/target/linux/x86/image/systemdboot-entry.cfg
new file mode 100644
index 0000000000..cf6bc659d0
--- /dev/null
+++ b/target/linux/x86/image/systemdboot-entry.cfg
@@ -0,0 +1,4 @@
+title @TITLE@
+linux /boot/vmlinuz
+options @GPT_ROOTPART@ @CMDLINE@ noinitrd
+architecture x64
diff --git a/target/linux/x86/image/systemdboot-loader.conf b/target/linux/x86/image/systemdboot-loader.conf
new file mode 100644
index 0000000000..533d233153
--- /dev/null
+++ b/target/linux/x86/image/systemdboot-loader.conf
@@ -0,0 +1 @@
+timeout menu-disabled
-- 
2.47.3




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