diff --git a/include/mbedtls/check_config.h b/include/mbedtls/check_config.h
index 4965e1743..ede070405 100644
--- a/include/mbedtls/check_config.h
+++ b/include/mbedtls/check_config.h
@@ -134,7 +134,7 @@
 #error "MBEDTLS_ECDSA_DETERMINISTIC defined, but not all prerequisites"
 #endif
 
-#if defined(MBEDTLS_ECP_C) && ( !defined(MBEDTLS_BIGNUM_C) || (   \
+#if defined(MBEDTLS_ECP_C) && ( !defined(MBEDTLS_BIGNUM_C) || (    \
     !defined(MBEDTLS_ECP_DP_SECP192R1_ENABLED) &&                  \
     !defined(MBEDTLS_ECP_DP_SECP224R1_ENABLED) &&                  \
     !defined(MBEDTLS_ECP_DP_SECP256R1_ENABLED) &&                  \
@@ -145,7 +145,9 @@
     !defined(MBEDTLS_ECP_DP_BP512R1_ENABLED)   &&                  \
     !defined(MBEDTLS_ECP_DP_SECP192K1_ENABLED) &&                  \
     !defined(MBEDTLS_ECP_DP_SECP224K1_ENABLED) &&                  \
-    !defined(MBEDTLS_ECP_DP_SECP256K1_ENABLED) ) )
+    !defined(MBEDTLS_ECP_DP_SECP256K1_ENABLED) &&                  \
+    !defined(MBEDTLS_ECP_DP_CURVE25519_ENABLED) &&                 \
+    !defined(MBEDTLS_ECP_DP_CURVE448_ENABLED) ) )
 #error "MBEDTLS_ECP_C defined, but not all prerequisites"
 #endif
 
diff --git a/include/mbedtls/rsa.h b/include/mbedtls/rsa.h
index 840540b0d..ec8d0d8de 100644
--- a/include/mbedtls/rsa.h
+++ b/include/mbedtls/rsa.h
@@ -907,7 +907,8 @@ int mbedtls_rsa_rsaes_oaep_decrypt( mbedtls_rsa_context *ctx,
  *                 the size of the hash corresponding to \p md_alg.
  * \param sig      The buffer to hold the signature. This must be a writable
  *                 buffer of length \c ctx->len Bytes. For example, \c 256 Bytes
- *                 for an 2048-bit RSA modulus.
+ *                 for an 2048-bit RSA modulus. A buffer length of
+ *                 #MBEDTLS_MPI_MAX_SIZE is always safe.
  *
  * \return         \c 0 if the signing operation was successful.
  * \return         An \c MBEDTLS_ERR_RSA_XXX error code on failure.
@@ -954,7 +955,8 @@ int mbedtls_rsa_pkcs1_sign( mbedtls_rsa_context *ctx,
  *                 the size of the hash corresponding to \p md_alg.
  * \param sig      The buffer to hold the signature. This must be a writable
  *                 buffer of length \c ctx->len Bytes. For example, \c 256 Bytes
- *                 for an 2048-bit RSA modulus.
+ *                 for an 2048-bit RSA modulus. A buffer length of
+ *                 #MBEDTLS_MPI_MAX_SIZE is always safe.
  *
  * \return         \c 0 if the signing operation was successful.
  * \return         An \c MBEDTLS_ERR_RSA_XXX error code on failure.
@@ -1015,7 +1017,8 @@ int mbedtls_rsa_rsassa_pkcs1_v15_sign( mbedtls_rsa_context *ctx,
  *                 the size of the hash corresponding to \p md_alg.
  * \param sig      The buffer to hold the signature. This must be a writable
  *                 buffer of length \c ctx->len Bytes. For example, \c 256 Bytes
- *                 for an 2048-bit RSA modulus.
+ *                 for an 2048-bit RSA modulus. A buffer length of
+ *                 #MBEDTLS_MPI_MAX_SIZE is always safe.
  *
  * \return         \c 0 if the signing operation was successful.
  * \return         An \c MBEDTLS_ERR_RSA_XXX error code on failure.