diff --git a/dist/tools/buildsystem_sanity_check/check.sh b/dist/tools/buildsystem_sanity_check/check.sh
index bcf61dfa7a01..a1b32bc6ef1f 100755
--- a/dist/tools/buildsystem_sanity_check/check.sh
+++ b/dist/tools/buildsystem_sanity_check/check.sh
@@ -78,6 +78,7 @@ UNEXPORTED_VARIABLES+=('DEBUG_ADAPTER' 'DEBUG_ADAPTER_ID')
 UNEXPORTED_VARIABLES+=('PROGRAMMER_SERIAL')
 UNEXPORTED_VARIABLES+=('STLINK_VERSION')
 UNEXPORTED_VARIABLES+=('PORT_LINUX' 'PORT_DARWIN')
+UNEXPORTED_VARIABLES+=('PORT[ ?=:]' 'PORT$')
 
 EXPORTED_VARIABLES_ONLY_IN_VARS=()
 check_not_exporting_variables() {