diff --git a/features/cellular/UNITTESTS/target_h/platform/mbed_retarget.h b/features/cellular/UNITTESTS/target_h/platform/mbed_retarget.h
index 8d2375f1f1..796e687292 100644
--- a/features/cellular/UNITTESTS/target_h/platform/mbed_retarget.h
+++ b/features/cellular/UNITTESTS/target_h/platform/mbed_retarget.h
@@ -17,3 +17,4 @@
 
 #include <sys/types.h>
 #define EAGAIN 11
+#define ENOTTY 25