diff --git a/tools/catalyst-auto b/tools/catalyst-auto
index f8258545..0cd9275f 100755
--- a/tools/catalyst-auto
+++ b/tools/catalyst-auto
@@ -268,6 +268,7 @@ run_catalyst_commands() {
 
 	# Some configs will set this explicitly, so don't clobber it.
 	: ${BUILD_SRCDIR_BASE:=$(catalyst_var storedir)}
+	: ${BUILD_SRCDIR_BASE:=/var/tmp/catalyst}
 
 	# See if we had a recent success.
 	if [[ ${lastrun} != 0 ]]; then