diff --git a/include/mbedtls/entropy_poll.h b/include/mbedtls/entropy_poll.h
index 430e865..81258d5 100644
--- a/include/mbedtls/entropy_poll.h
+++ b/include/mbedtls/entropy_poll.h
@@ -41,7 +41,9 @@
 #define MBEDTLS_ENTROPY_MIN_PLATFORM     32     /**< Minimum for platform source    */
 #define MBEDTLS_ENTROPY_MIN_HAVEGE       32     /**< Minimum for HAVEGE             */
 #define MBEDTLS_ENTROPY_MIN_HARDCLOCK     4     /**< Minimum for mbedtls_timing_hardclock()        */
+#if !defined(MBEDTLS_ENTROPY_MIN_HARDWARE)
 #define MBEDTLS_ENTROPY_MIN_HARDWARE     32     /**< Minimum for the hardware source */
+#endif
 
 /**
  * \brief           Entropy poll callback that provides 0 entropy.