diff --git a/live-build/ubuntu-cpc/hooks/032-disk-image.binary b/live-build/ubuntu-cpc/hooks/032-disk-image.binary
index 1eae3308..8b6dab46 100755
--- a/live-build/ubuntu-cpc/hooks/032-disk-image.binary
+++ b/live-build/ubuntu-cpc/hooks/032-disk-image.binary
@@ -2,6 +2,10 @@
 
 . /build/config/functions
 
+BOOTPART_START=
+BOOTPART_END=
+BOOT_MOUNTPOINT=
+
 case $ARCH in
 	ppc64el)
 		echo "ppc64el disk images are handled separately"