diff --git a/src/swtpm_setup/swtpm_setup.sh.in b/src/swtpm_setup/swtpm_setup.sh.in
index 6e22e09..ebe5f6c 100755
--- a/src/swtpm_setup/swtpm_setup.sh.in
+++ b/src/swtpm_setup/swtpm_setup.sh.in
@@ -184,7 +184,7 @@ call_create_certs()
 		logparam="--logfile $LOGFILE"
 	fi
 
-	params+="$(get_tpm_spec_parameters) "
+	params="${params} $(get_tpm_spec_parameters)"
 	[ $? -ne 0 ] && return 1
 
 	if [ $((flags & SETUP_EK_CERT_F)) -ne 0 ] || \