diff --git a/live-build/auto/config b/live-build/auto/config
index 4f7cf9b9..1f812180 100755
--- a/live-build/auto/config
+++ b/live-build/auto/config
@@ -897,7 +897,7 @@ case $PROJECT in
 				# the GA and HWE kernels (in separate layers) so this code is
 				# written generically to support both even though a lot of the
 				# time only one kernel is offered.
-				case ${SUBARCH-} in
+				case ${SUBARCH:-} in
 					intel-iot)
 						variants='intel'
 						;;