diff --git a/configs/config-ccm-psk-tls1_2.h b/configs/config-ccm-psk-tls1_2.h
index c9b58dd..e0f50ea 100644
--- a/configs/config-ccm-psk-tls1_2.h
+++ b/configs/config-ccm-psk-tls1_2.h
@@ -55,6 +55,9 @@
 #define MBEDTLS_SSL_SRV_C
 #define MBEDTLS_SSL_TLS_C
 
+/* Save ROM by excluded SHA-2 variant that we don't need */
+#define MBEDTLS_SHA256_NO_SHA224
+
 /* Save RAM at the expense of ROM */
 #define MBEDTLS_AES_ROM_TABLES
 
diff --git a/configs/config-suite-b.h b/configs/config-suite-b.h
index 18e2c40..d6891fa 100644
--- a/configs/config-suite-b.h
+++ b/configs/config-suite-b.h
@@ -78,6 +78,9 @@
 #define MBEDTLS_CERTS_C
 #define MBEDTLS_PEM_PARSE_C
 
+/* Save ROM by excluded SHA-2 variant that we don't need */
+#define MBEDTLS_SHA256_NO_SHA224
+
 /* Save RAM at the expense of ROM */
 #define MBEDTLS_AES_ROM_TABLES
 
diff --git a/configs/config-thread.h b/configs/config-thread.h
index 4fa0b8d..da8ac7a 100644
--- a/configs/config-thread.h
+++ b/configs/config-thread.h
@@ -88,6 +88,9 @@
 #define MBEDTLS_ECP_MAX_BITS             256
 #define MBEDTLS_MPI_MAX_SIZE              32 // 256 bits is 32 bytes
 
+/* Save ROM by excluded SHA-2 variant that we don't need */
+#define MBEDTLS_SHA256_NO_SHA224
+
 /* Save ROM and a few bytes of RAM by specifying our own ciphersuite list */
 #define MBEDTLS_SSL_CIPHERSUITES MBEDTLS_TLS_ECJPAKE_WITH_AES_128_CCM_8