diff --git a/tests/mutex_order/Makefile b/tests/mutex_order/Makefile
index 1d4146a981..1465828169 100644
--- a/tests/mutex_order/Makefile
+++ b/tests/mutex_order/Makefile
@@ -5,3 +5,8 @@ BOARD_INSUFFICIENT_MEMORY := stm32f0discovery weio nucleo-f030 nucleo32-f042 nuc
                              nucleo-l053
 
 include $(RIOTBASE)/Makefile.include
+
+test:
+# `testrunner` calls `make term` recursively, results in duplicated `TERMFLAGS`.
+# So clears `TERMFLAGS` before run.
+	TERMFLAGS= tests/01-run.py
diff --git a/tests/rmutex/Makefile b/tests/rmutex/Makefile
index 9c813d6be1..d0eaf136a7 100644
--- a/tests/rmutex/Makefile
+++ b/tests/rmutex/Makefile
@@ -5,3 +5,8 @@ BOARD_INSUFFICIENT_MEMORY := stm32f0discovery weio nucleo-f030 nucleo32-f031 \
                              nucleo32-f042 nucleo-l053
 
 include $(RIOTBASE)/Makefile.include
+
+test:
+# `testrunner` calls `make term` recursively, results in duplicated `TERMFLAGS`.
+# So clears `TERMFLAGS` before run.
+	TERMFLAGS= tests/01-run.py
diff --git a/tests/thread_flood/Makefile b/tests/thread_flood/Makefile
index 67d8dd4048..1a78b3b869 100644
--- a/tests/thread_flood/Makefile
+++ b/tests/thread_flood/Makefile
@@ -4,3 +4,8 @@ include ../Makefile.tests_common
 DISABLE_MODULE += auto_init
 
 include $(RIOTBASE)/Makefile.include
+
+test:
+# `testrunner` calls `make term` recursively, results in duplicated `TERMFLAGS`.
+# So clears `TERMFLAGS` before run.
+	TERMFLAGS= tests/test_thread.py