diff --git a/cpu/esp32/freertos/semphr.c b/cpu/esp32/freertos/semphr.c
index 04ee642d80..42436b2452 100644
--- a/cpu/esp32/freertos/semphr.c
+++ b/cpu/esp32/freertos/semphr.c
@@ -94,7 +94,7 @@ BaseType_t xSemaphoreTake (SemaphoreHandle_t xSemaphore,
         case queueQUEUE_TYPE_MUTEX:
         {
             if (xTicksToWait == 0) {
-                return (mutex_trylock(mutex) == 0) ? pdTRUE : pdFALSE;
+                return (mutex_trylock(mutex) == 1) ? pdTRUE : pdFALSE;
             }
             else {
                 mutex_lock(mutex);