Index: tools/grub/grub-update.sh
===================================================================
--- tools/grub/grub-update.sh	(revision a114e0953ae86477f5a778f6e683302eb54ec781)
+++ tools/grub/grub-update.sh	(revision 5b5f3eba514569bf4a626f320e26c06dde93f11b)
@@ -40,10 +40,15 @@
 grub_rev="bc220962e366b1b46769ed6f9fa5be603ba58ab5"
 
+build_ia32amd64_pc=false
+build_ia32amd64_efi=false
+build_arm64_efi=false
+
 function grub_build()
 {
-	target="$1"
-	platform="$2"
+	platform="$1"
+	conf_target="$2"
+	conf_platform="$3"
 
-	./configure --prefix="$builddir/$target-$platform" --target="$target" --with-platform="$platform" --disable-werror || exit 1
+	./configure --prefix="$builddir/$platform" --target="$conf_target" --with-platform="$conf_platform" --disable-werror || exit 1
 	make clean || exit 1
 	make install || exit 1
@@ -55,10 +60,52 @@
 	platform="$2"
 
-	rm -rf "$helenosdir"/boot/"$gdir"/"$platform" || exit 1
-	cp -R "$builddir"/"$platform"/lib64/grub/"$platform" "$helenosdir"/boot/"$gdir" || exit 1
-	rm -f "$helenosdir"/boot/"$gdir"/"$platform"/*.image || exit 1
-	rm -f "$helenosdir"/boot/"$gdir"/"$platform"/*.module || exit 1
-	git add "$helenosdir"/boot/"$gdir"/"$platform" || exit 1
+	echo "$grub_rev" > "$helenosdir"/boot/grub/"$gdir"/REVISION || exit 1
+	rm -rf "$helenosdir"/boot/grub/"$gdir"/"$platform" || exit 1
+	cp -R "$builddir"/"$platform"/lib*/grub/"$platform" "$helenosdir"/boot/grub/"$gdir" || exit 1
+	rm -f "$helenosdir"/boot/grub/"$gdir"/"$platform"/*.image || exit 1
+	rm -f "$helenosdir"/boot/grub/"$gdir"/"$platform"/*.module || exit 1
+	git add "$helenosdir"/boot/grub/"$gdir"/"$platform" || exit 1
 }
+
+function show_usage()
+{
+	echo "Script to generate/update prebuild Grub2 in HelenOS source tree"
+	echo
+	echo "Syntax:"
+	echo " $0 <target>"
+	echo
+	echo "Possible targets are:"
+	echo " ia32+amd64-pc"
+	echo " ia32+amd64-efi"
+	echo " arm64-efi"
+	echo " all             build all targets"
+	echo
+
+	exit 3
+}
+
+if [ "$#" -ne "1" ] ; then
+	show_usage
+fi
+
+case "$1" in
+	ia32+amd64-pc)
+		build_ia32amd64_pc=true
+		;;
+	ia32+amd64-efi)
+		build_ia32amd64_efi=true
+		;;
+	arm64-efi)
+		build_arm64_efi=true
+		;;
+	all)
+		build_ia32amd64_pc=true
+		build_ia32amd64_efi=true
+		build_arm64_efi=true
+		;;
+	*)
+		show_usage
+		;;
+esac
 
 # Prepare a clone of Grub2 repo
@@ -72,41 +119,68 @@
 git reset --hard "$grub_rev" || exit 1
 
-echo "$grub_rev" >"$helenosdir"/boot/grub/ia32-pc/REVISION || exit 1
-echo "$grub_rev" > "$helenosdir"/boot/grub/ia32-efi/REVISION || exit 1
+./autogen.sh || exit 1
 
-# Build each platform to a different directory
-./autogen.sh || exit 1
-grub_build i386 pc
-grub_build i386 efi
-grub_build x86_64 efi
+if $build_ia32amd64_pc ; then
+	cd "$workdir" || exit 1
+	grub_build i386-pc i386 pc
 
-# Extract El Torrito boot image for i386-pc
-cd "$helenosdir"/boot/grub/ia32-pc || exit 1
-rm -f pc.img || exit 1
-"$builddir"/i386-pc/bin/grub-mkrescue -o phony --xorriso="$origdir/getimage.sh" || exit 1
+	# Extract El Torrito boot image for i386-pc
+	cd "$helenosdir"/boot/grub/ia32-pc || exit 1
+	rm -f pc.img || exit 1
+	"$builddir"/i386-pc/bin/grub-mkrescue -o phony --xorriso="$origdir/getimage.sh" || exit 1
 
-# Extract El Torrito boot image for i386-efi
-cd "$helenosdir"/boot/grub/ia32-efi || exit 1
-rm -f efi.img.gz || exit 1
-"$builddir"/i386-efi/bin/grub-mkrescue -o phony --xorriso="$origdir/getimage.sh" || exit 1
-mv efi.img i386-efi.img
+	grub_files_update ia32-pc i386-pc
+fi
 
-# Extract El Torrito boot image for x86_64-efi
-cd "$helenosdir"/boot/grub/ia32-efi || exit 1
-rm -f efi.img.gz || exit 1
-"$builddir"/x86_64-efi/bin/grub-mkrescue -o phony --xorriso="$origdir/getimage.sh" || exit 1
+if $build_ia32amd64_efi ; then
+	cd "$workdir" || exit 1
 
-# Combine El Torrito boot images for x86_64-efi and i386-efi
-mkdir tmp || exit 1
-mcopy -ns -i i386-efi.img ::efi tmp || exit 1
-mcopy -s -i efi.img tmp/* :: || exit 1
-gzip efi.img || exit 1
-rm -rf tmp || exit 1
-rm -f i386-efi.img || exit 1
+	# Build each platform to a different directory
+	grub_build i386-efi i386 efi
+	grub_build x86_64-efi x86_64 efi
 
-# Update Grub files for all platforms
-grub_files_update grub/ia32-pc i386-pc
-grub_files_update grub/ia32-efi i386-efi
-grub_files_update grub/ia32-efi x86_64-efi
+	# Extract El Torrito boot image for i386-efi
+	cd "$helenosdir"/boot/grub/ia32-efi || exit 1
+	rm -f efi.img.gz || exit 1
+	"$builddir"/i386-efi/bin/grub-mkrescue -o phony --xorriso="$origdir/getimage.sh" || exit 1
+	mv efi.img i386-efi.img
+
+	# Extract El Torrito boot image for x86_64-efi
+	cd "$helenosdir"/boot/grub/ia32-efi || exit 1
+	rm -f efi.img.gz || exit 1
+	"$builddir"/x86_64-efi/bin/grub-mkrescue -o phony --xorriso="$origdir/getimage.sh" || exit 1
+
+	# Combine El Torrito boot images for x86_64-efi and i386-efi
+	mkdir tmp || exit 1
+	mcopy -ns -i i386-efi.img ::efi tmp || exit 1
+	mcopy -s -i efi.img tmp/* :: || exit 1
+	gzip efi.img || exit 1
+	rm -rf tmp || exit 1
+	rm -f i386-efi.img || exit 1
+
+	# Update Grub files for all platforms
+	grub_files_update ia32-efi i386-efi
+	grub_files_update ia32-efi x86_64-efi
+fi
+
+if $build_arm64_efi ; then
+	cd "$workdir" || exit 1
+
+	# Check that the expected compiler is present on PATH
+	if ! [ -x "$(command -v aarch64-linux-gnu-gcc)" ] ; then
+		echo "Error: aarch64-linux-gnu-gcc is missing" >&2
+		exit 1
+	fi
+
+	grub_build arm64-efi aarch64-linux-gnu efi
+
+	# Extract El Torrito boot image for arm64-efi
+	cd "$helenosdir"/boot/grub/arm64-efi || exit 1
+	rm -f efi.img.gz || exit 1
+	"$builddir"/arm64-efi/bin/grub-mkrescue -o phony --xorriso="$origdir/getimage.sh" || exit 1
+	gzip efi.img || exit 1
+
+	grub_files_update arm64-efi arm64-efi
+fi
 
 echo "GRUB update successful."