Add an extra di-specific version of the UEFI netboot image

Identical to the normal netboot image, but With a different baked-in
prefix value ("$vendor-installer/$ARCH/grub" instead of "/grub").

Helps to fix #928750, making d-i consistent in terms of PXE setup.

debian/build-efi-images

@@ -20,16 +20,17 @@ set -e
 
 # Make EFI boot images for signing.
 
-if [ $# -lt 5 ]; then
-	echo "usage: $0 GRUB-MKIMAGE GRUB-CORE OUTPUT-DIRECTORY PLATFORM EFI-NAME [EFI-VENDOR]"
+if [ $# -lt 6 ]; then
+	echo "usage: $0 GRUB-MKIMAGE GRUB-CORE OUTPUT-DIRECTORY DEB-ARCH PLATFORM EFI-NAME [EFI-VENDOR]"
 fi
 
 grub_mkimage="$1"
 grub_core="$2"
 outdir="$3"
-platform="$4"
-efi_name="$5"
-efi_vendor="${6:-$(dpkg-vendor --query vendor | tr '[:upper:]' '[:lower:]')}"
+deb_arch="$4"
+platform="$5"
+efi_name="$6"
+efi_vendor="${7:-$(dpkg-vendor --query vendor | tr '[:upper:]' '[:lower:]')}"
 
 # mkfs.msdos may not be on the default PATH.
 export PATH="$PATH:/sbin:/usr/sbin"
@@ -191,15 +192,29 @@ NET_MODULES="$CD_MODULES
 	tftp
 	"
 
+# CD boot image
 "$grub_mkimage" -O "$platform" -o "$outdir/gcd$efi_name.efi" \
 	-d "$grub_core" \
 	-c "$workdir/grub-bootstrap.cfg" -m "$workdir/memdisk.fat" \
 	-p /boot/grub \
 	$CD_MODULES
+
+# Normal disk boot image
 "$grub_mkimage" -O "$platform" -o "$outdir/grub$efi_name.efi" \
 	-d "$grub_core" -p "/EFI/$efi_vendor" $GRUB_MODULES
+
+# Normal network boot image
 "$grub_mkimage" -O "$platform" -o "$outdir/grubnet$efi_name.efi" \
 	-d "$grub_core" -c "$workdir/grub-bootstrap.cfg" \
-	-m "$workdir/memdisk-netboot.fat" -p /grub $NET_MODULES
+	-m "$workdir/memdisk-netboot.fat" \
+	-p /grub $NET_MODULES
+
+# Special network boot image for d-i to use. Just the same as the
+# normal network boot image, but with a different value baked in for
+# the prefix setting
+"$grub_mkimage" -O "$platform" -o "$outdir/grubnet$efi_name-installer.efi" \
+	-d "$grub_core" -c "$workdir/grub-bootstrap.cfg" \
+	-m "$workdir/memdisk-netboot.fat" \
+	-p "${efi_vendor}-installer/$deb_arch/grub" $NET_MODULES
 
 exit 0

debian/changelog

@@ -7,6 +7,8 @@ grub2 (2.04~rc1-2) UNRELEASED; urgency=medium
   * Add the ntfs module to signed UEFI images. Closes: #923855
   * Add the cpuid module to signed UEFI images. Closes: #928628
   * Add the play module to signed UEFI images. Closes: #930290
+  * Add an extra di-specific version of the UEFI netboot image with a
+    different baked-in prefix value. Helps to fix #928750.
 
  -- Colin Watson <cjwatson@debian.org>  Tue, 04 Jun 2019 19:41:22 +0100
 

debian/rules

@@ -219,7 +219,7 @@ debian/stamps/build-grub-efi-ia32 debian/stamps/build-grub-efi-amd64 debian/stam
 		obj/grub-$(COMMON_PLATFORM)/grub-mkimage \
 		obj/$(package)/grub-core \
 		obj/monolithic/$(package) \
-		$(SB_PLATFORM) $(SB_EFI_NAME) $(SB_EFI_VENDOR)
+		$(DEB_HOST_ARCH) $(SB_PLATFORM) $(SB_EFI_NAME) $(SB_EFI_VENDOR)
 	touch $@
 
 debian/stamps/build-grub-xen-host-i386: PVBOOT_ARCH := i386

debian/signing-template.json.in

@@ -6,6 +6,7 @@
             "files": [
                 {"sig_type": "efi", "file": "usr/lib/grub/@efi_platform@/monolithic/gcd@efi@.efi"},
                 {"sig_type": "efi", "file": "usr/lib/grub/@efi_platform@/monolithic/grubnet@efi@.efi"},
+                {"sig_type": "efi", "file": "usr/lib/grub/@efi_platform@/monolithic/grubnet@efi@-installer.efi"},
                 {"sig_type": "efi", "file": "usr/lib/grub/@efi_platform@/monolithic/grub@efi@.efi"}
             ]
         }