diff --git a/library/ecp.c b/library/ecp.c
index 0aa61f1..94c7960 100644
--- a/library/ecp.c
+++ b/library/ecp.c
@@ -3000,13 +3000,12 @@
  * Write a private key.
  */
 int mbedtls_ecp_write_key( mbedtls_ecp_group_id grp_id, mbedtls_ecp_keypair *key,
-                           size_t *olen, unsigned char *buf, size_t buflen )
+                           unsigned char *buf, size_t buflen )
 {
     int ret = 0;
 
     ECP_VALIDATE_RET( key  != NULL );
     ECP_VALIDATE_RET( buf  != NULL );
-    ECP_VALIDATE_RET( olen != NULL );
 
     if( ( ret = mbedtls_ecp_group_load( &key->grp, grp_id ) ) != 0 )
         return( ret );
@@ -3022,7 +3021,6 @@
                 return MBEDTLS_ERR_ECP_BUFFER_TOO_SMALL;
 
             MBEDTLS_MPI_CHK( mbedtls_mpi_write_binary_le( &key->d, buf, buflen ) );
-            *olen = ECP_CURVE25519_KEY_SIZE;
         }
         else
             ret = MBEDTLS_ERR_ECP_FEATURE_UNAVAILABLE;
@@ -3033,7 +3031,6 @@
     if( mbedtls_ecp_get_type( &key->grp ) == MBEDTLS_ECP_TYPE_SHORT_WEIERSTRASS )
     {
         MBEDTLS_MPI_CHK( mbedtls_mpi_write_binary( &key->d, buf, buflen ) );
-        *olen = mbedtls_mpi_size( &key->d );
     }
 
 #endif
diff --git a/library/pkwrite.c b/library/pkwrite.c
index 914b33f..4288cd7 100644
--- a/library/pkwrite.c
+++ b/library/pkwrite.c
@@ -166,10 +166,9 @@
 {
     int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     size_t byte_length = ( ec->grp.pbits + 7 ) / 8;
-    size_t output_length;
     unsigned char tmp[MBEDTLS_ECP_MAX_BYTES];
 
-    ret = mbedtls_ecp_write_key( ec->grp.id, ec, &output_length, tmp, byte_length );
+    ret = mbedtls_ecp_write_key( ec->grp.id, ec, tmp, byte_length );
     if( ret != 0 )
         goto exit;
     ret = mbedtls_asn1_write_octet_string( p, start, tmp, byte_length );
diff --git a/library/psa_crypto.c b/library/psa_crypto.c
index 1151d17..a620d30 100644
--- a/library/psa_crypto.c
+++ b/library/psa_crypto.c
@@ -1321,14 +1321,13 @@
     if( PSA_KEY_TYPE_IS_ECC_KEY_PAIR( slot->attr.type ) && !export_public_key )
     {
         psa_status_t status;
-        size_t actual_data_size;
 
         size_t bytes = PSA_BITS_TO_BYTES( slot->attr.bits );
         if( bytes > data_size )
             return( PSA_ERROR_BUFFER_TOO_SMALL );
         status = mbedtls_to_psa_error(
             mbedtls_ecp_write_key(slot->data.ecp->grp.id, slot->data.ecp,
-                                  &actual_data_size, data, bytes) );
+                                  data, bytes) );
         if( status != PSA_SUCCESS )
             return( status );
         memset( data + bytes, 0, data_size - bytes );