diff --git a/library/error.c b/library/error.c
index 0ea3c29..86586dd 100644
--- a/library/error.c
+++ b/library/error.c
@@ -149,6 +149,10 @@
 #include "polarssl/x509.h"
 #endif
 
+#if defined(POLARSSL_X509_WRITE_C)
+#include "polarssl/x509write.h"
+#endif
+
 #if defined(POLARSSL_XTEA_C)
 #include "polarssl/xtea.h"
 #endif
@@ -251,7 +255,7 @@
         if( use_ret == -(POLARSSL_ERR_PK_MALLOC_FAILED) )
             snprintf( buf, buflen, "PK - Memory alloation failed" );
         if( use_ret == -(POLARSSL_ERR_PK_TYPE_MISMATCH) )
-            snprintf( buf, buflen, "PK - Type mismatch, eg attempt to use a RSA key as EC, or to modify key type" );
+            snprintf( buf, buflen, "PK - Type mismatch, eg attempt to encrypt with an ECDSA key" );
         if( use_ret == -(POLARSSL_ERR_PK_BAD_INPUT_DATA) )
             snprintf( buf, buflen, "PK - Bad input parameters to function" );
 #endif /* POLARSSL_PK_C */
@@ -432,6 +436,15 @@
             snprintf( buf, buflen, "X509 - Elliptic curve is unsupported (only NIST curves are supported)" );
 #endif /* POLARSSL_X509_PARSE_C */
 
+#if defined(POLARSSL_X509_WRITE_C)
+        if( use_ret == -(POLARSSL_ERR_X509WRITE_UNKNOWN_OID) )
+            snprintf( buf, buflen, "X509WRITE - Requested OID is unknown" );
+        if( use_ret == -(POLARSSL_ERR_X509WRITE_BAD_INPUT_DATA) )
+            snprintf( buf, buflen, "X509WRITE - Failed to allocate memory" );
+        if( use_ret == -(POLARSSL_ERR_X509WRITE_MALLOC_FAILED) )
+            snprintf( buf, buflen, "X509WRITE - Failed to allocate memory" );
+#endif /* POLARSSL_X509_WRITE_C */
+
         if( strlen( buf ) == 0 )
             snprintf( buf, buflen, "UNKNOWN ERROR CODE (%04X)", use_ret );
     }