1 files changed, 49 insertions, 0 deletions
diff --git a/surface-editbootconfig.sh b/surface-editbootconfig.sh
new file mode 100755
index 0000000..e6cc67c
--- /dev/null
+++ b/surface-editbootconfig.sh
@@ -0,0 +1,49 @@
+#!/bin/bash
+# Surface Pro 12" (Snapdragon X1P-42-100): put the device tree on the ISO.
+#
+# kiwi has no device tree support of its own, and the ISO's GRUB needs the dtb
+# as a plain file it can read: it loads it with a "devicetree" line before the
+# kernel (see grub-arm.cfg.iso-template), it cannot read the erofs root image,
+# and kiwi copies only the kernel and the initrd into the ISO's loader
+# directory.
+#
+# editbootconfig is the one hook that reaches the ISO tree. kiwi's live builder
+# calls it with "iso:<media dir>" as the first argument and the image root as
+# the working directory, after setup_media_loader_directory has created the
+# loader directory and the GRUB config has been written. So the dtb can be
+# taken straight out of the kernel-surface RPM installed in the image root,
+# which is why config-cdroot.tar is no longer needed to carry a committed copy.
+
+set -euo pipefail
+
+target="${1:-}"
+case "${target}" in
+	iso:*) media_dir="${target#iso:}" ;;
+	*)
+		echo "surface-editbootconfig: expected an iso: target, got '${target}'" >&2
+		exit 1
+		;;
+esac
+
+dtb_name=x1p42100-microsoft-sp12in.dtb
+
+# The working directory is the image root, so this is kernel-surface's own copy,
+# under a directory named for the kernel version because that package is
+# installonly. config.sh has already failed the build if it is not there.
+dtb_src=$(ls -1 usr/lib/surface-dtb/*/"${dtb_name}" 2>/dev/null | sort -V | tail -n1)
+if [[ -z "${dtb_src}" ]]; then
+	echo "surface-editbootconfig: no ${dtb_name} under usr/lib/surface-dtb/ in the image root" >&2
+	exit 1
+fi
+
+# ${bootpath} in the GRUB template is /boot/<kiwi platform name>/loader. Read
+# the directory back off the media tree rather than recomputing that name, so
+# the dtb cannot end up somewhere the GRUB config does not look.
+loader_dirs=("${media_dir}"/boot/*/loader)
+if [[ ${#loader_dirs[@]} -ne 1 || ! -d "${loader_dirs[0]}" ]]; then
+	echo "surface-editbootconfig: expected one ${media_dir}/boot/*/loader, found ${#loader_dirs[@]}" >&2
+	exit 1
+fi
+
+install -Dm644 "${dtb_src}" "${loader_dirs[0]}/${dtb_name}"
+echo "surface-editbootconfig: staged ${loader_dirs[0]}/${dtb_name}"