diff -Naur grub-2.04/util/grub-mkconfig.in grub-2.04-magellan/util/grub-mkconfig.in
--- grub-2.04/util/grub-mkconfig.in	2019-05-20 12:59:36.000000000 +0200
+++ grub-2.04-magellan/util/grub-mkconfig.in	2020-07-07 14:51:48.127358642 +0200
@@ -134,6 +134,14 @@
 # Device containing our userland.  Typically used for root= parameter.
 GRUB_DEVICE="`${grub_probe} --target=device /`"
 GRUB_DEVICE_UUID="`${grub_probe} --device ${GRUB_DEVICE} --target=fs_uuid 2> /dev/null`" || true
+# workaround unknown partion types
+if [ x"${GRUB_DEVICE_UUID}" = x ]
+then
+    if [ -x `type -P blkid` ]
+    then
+       GRUB_DEVICE_UUID="`blkid -s UUID -o value ${GRUB_DEVICE} 2> /dev/null`" || true
+    fi
+fi
 GRUB_DEVICE_PARTUUID="`${grub_probe} --device ${GRUB_DEVICE} --target=partuuid 2> /dev/null`" || true
 
 # Device containing our /boot partition.  Usually the same as GRUB_DEVICE.