https://bugs.gentoo.org/show_bug.cgi?id=426364
https://savannah.gnu.org/bugs/index.php?36839
--- util/grub-mkconfig_lib.in
+++ util/grub-mkconfig_lib.in
@@ -255,19 +255,19 @@
   echo "$version_find_latest_a"
 }
 
-# One layer of quotation is eaten by "", the second by sed, and the third by
-# printf; so this turns ' into \'.  Note that you must use the output of
+# One layer of quotation is eaten by "" and the second by
+# sed; so this turns ' into \'.  Note that you must use the output of
 # this function in a printf format string.
 
 grub_quote () {
-  sed "s/'/'\\\\\\\\''/g"
+  sed "s/'/'\\\\''/g"
 }
 
 gettext_quoted () {
-  gettext "$@" | sed "s/'/'\\\\\\\\''/g"
+  gettext "$@" | grub_quote
 }
 
-# Run the first argument through gettext_quoted, and then pass that and all
+# Run the first argument through gettext, and then pass that and all
 # remaining arguments to printf.  This is a useful abbreviation and tends to
 # be easier to type.
 gettext_printf () {

=== modified file 'util/grub.d/10_hurd.in'
--- util/grub.d/10_hurd.in
+++ util/grub.d/10_hurd.in
@@ -117,7 +117,7 @@
       opts=
   fi
   sed "s/^/$submenu_indentation/" << EOF
-	echo		'$message'
+	echo		'$(echo "$message" | grub_quote)'
 	multiboot	${kernel} root=device:${GRUB_DEVICE#/dev/} $opts ${GRUB_CMDLINE_GNUMACH}
 EOF
 
@@ -133,7 +133,7 @@
   fi
 
   sed "s/^/$submenu_indentation/" << EOF
-	echo		'$message'
+	echo		'$(echo "$message" | grub_quote)'
 	module		/hurd/${hurd_fs}.static ${hurd_fs} $opts \\
 			--multiboot-command-line='\${kernel-command-line}' \\
 			--host-priv-port='\${host-port}' \\
--- util/grub.d/10_illumos.in
+++ util/grub.d/10_illumos.in
@@ -46,6 +46,7 @@
 		ISADIR=
 	fi
 	zfs-bootfs $($grub_mkrelpath /) ZFS_BOOTFS
+        echo '$(echo "$message" | grub_quote)'
 	multiboot $($grub_mkrelpath /platform/i86pc/kernel)/\$ISADIR/unix /platform/i86pc/kernel/\$ISADIR/unix -B \$ZFS_BOOTFS,console=text
 	module $($grub_mkrelpath /platform/i86pc)/\$ISADIR/boot_archive /platform/i86pc/\$ISADIR/boot_archive
 }
--- util/grub.d/10_kfreebsd.in
+++ util/grub.d/10_kfreebsd.in
@@ -100,7 +100,7 @@
   printf '%s\n' "${prepare_boot_cache}" | sed "s/^/$submenu_indentation/"
   message="$(gettext_printf "Loading kernel of FreeBSD %s ..." ${version})"
   sed "s/^/$submenu_indentation/" << EOF
-	echo			'$message'
+	echo			'$(echo "$message" | grub_quote)'
 	kfreebsd		${rel_dirname}/${basename} ${args}
 EOF
 
--- util/grub.d/10_linux.in
+++ util/grub.d/10_linux.in
@@ -134,14 +134,14 @@
   fi
   message="$(gettext_printf "Loading Linux %s ..." ${version})"
   sed "s/^/$submenu_indentation/" << EOF
-	echo	'$message'
+	echo	'$(echo "$message" | grub_quote)'
 	linux	${rel_dirname}/${basename} root=${linux_root_device_thisversion} ro ${args}
 EOF
   if test -n "${initrd}" ; then
     # TRANSLATORS: ramdisk isn't identifier. Should be translated.
     message="$(gettext_printf "Loading initial ramdisk ...")"
     sed "s/^/$submenu_indentation/" << EOF
-	echo	'$message'
+	echo	'$(echo "$message" | grub_quote)'
 	initrd	${rel_dirname}/${initrd}
 EOF
   fi
--- util/grub.d/20_linux_xen.in
+++ util/grub.d/20_linux_xen.in
@@ -120,16 +120,16 @@
   xmessage="$(gettext_printf "Loading Xen %s ..." ${xen_version})"
   lmessage="$(gettext_printf "Loading Linux %s ..." ${version})"
   sed "s/^/$submenu_indentation/" << EOF
-	echo	'$xmessage'
+	echo	'$(echo "$xmessage" | grub_quote)'
 	multiboot	${rel_xen_dirname}/${xen_basename} placeholder ${xen_args}
-	echo	'$lmessage'
+	echo	'$(echo "$lmessage" | grub_quote)'
 	module	${rel_dirname}/${basename} placeholder root=${linux_root_device_thisversion} ro ${args}
 EOF
   if test -n "${initrd}" ; then
     # TRANSLATORS: ramdisk isn't identifier. Should be translated.
     message="$(gettext_printf "Loading initial ramdisk ...")"
     sed "s/^/$submenu_indentation/" << EOF
-	echo	'$message'
+	echo	'$(echo "$message" | grub_quote)'
 	module	${rel_dirname}/${initrd}
 EOF
   fi