diff --git a/library/ccm.c b/library/ccm.c
index 9911e0f..750ec9e 100644
--- a/library/ccm.c
+++ b/library/ccm.c
@@ -37,6 +37,7 @@
 #if defined(MBEDTLS_CCM_C)
 
 #include "mbedtls/ccm.h"
+#include "mbedtls/platform.h"
 #include "mbedtls/platform_util.h"
 
 #include <string.h>
@@ -74,7 +75,7 @@
                         const unsigned char *key,
                         unsigned int keybits )
 {
-    int ret;
+    int ret = MBEDTLS_ERR_PLATFORM_FAULT_DETECTED;
     const mbedtls_cipher_info_t *cipher_info;
 
     CCM_VALIDATE_RET( ctx != NULL );
@@ -98,7 +99,7 @@
         return( ret );
     }
 
-    return( 0 );
+    return( ret );
 }
 
 /*
@@ -155,7 +156,7 @@
                            const unsigned char *input, unsigned char *output,
                            unsigned char *tag, size_t tag_len )
 {
-    int ret;
+    int ret = MBEDTLS_ERR_PLATFORM_FAULT_DETECTED;
     unsigned char i;
     unsigned char q;
     size_t len_left, olen;
@@ -315,7 +316,7 @@
     CTR_CRYPT( y, y, 16 );
     mbedtls_platform_memcpy( tag, y, tag_len );
 
-    return( 0 );
+    return( ret );
 }
 
 /*
@@ -365,7 +366,7 @@
                       const unsigned char *input, unsigned char *output,
                       const unsigned char *tag, size_t tag_len )
 {
-    int ret;
+    int ret = MBEDTLS_ERR_PLATFORM_FAULT_DETECTED;
     unsigned char check_tag[16];
     unsigned char i;
     int diff;
@@ -394,7 +395,7 @@
         return( MBEDTLS_ERR_CCM_AUTH_FAILED );
     }
 
-    return( 0 );
+    return( ret );
 }
 
 int mbedtls_ccm_auth_decrypt( mbedtls_ccm_context *ctx, size_t length,
diff --git a/library/entropy.c b/library/entropy.c
index 6656ee8..f5d7d40 100644
--- a/library/entropy.c
+++ b/library/entropy.c
@@ -142,7 +142,7 @@
                         mbedtls_entropy_f_source_ptr f_source, void *p_source,
                         size_t threshold, int strong )
 {
-    int idx, ret = 0;
+    int idx, ret = MBEDTLS_ERR_PLATFORM_FAULT_DETECTED;
 
 #if defined(MBEDTLS_THREADING_C)
     if( ( ret = mbedtls_mutex_lock( &ctx->mutex ) ) != 0 )
@@ -162,6 +162,7 @@
     ctx->source[idx].strong    = strong;
 
     ctx->source_count++;
+    ret = 0;
 
 exit:
 #if defined(MBEDTLS_THREADING_C)
@@ -182,7 +183,7 @@
     unsigned char tmp[MBEDTLS_ENTROPY_BLOCK_SIZE];
     size_t use_len = len;
     const unsigned char *p = data;
-    int ret = 0;
+    int ret = MBEDTLS_ERR_PLATFORM_FAULT_DETECTED;
 
     if( use_len > MBEDTLS_ENTROPY_BLOCK_SIZE )
     {
@@ -234,7 +235,7 @@
 int mbedtls_entropy_update_manual( mbedtls_entropy_context *ctx,
                            const unsigned char *data, size_t len )
 {
-    int ret;
+    int ret = MBEDTLS_ERR_PLATFORM_FAULT_DETECTED;
 
 #if defined(MBEDTLS_THREADING_C)
     if( ( ret = mbedtls_mutex_lock( &ctx->mutex ) ) != 0 )
@@ -325,7 +326,7 @@
  */
 int mbedtls_entropy_gather( mbedtls_entropy_context *ctx )
 {
-    int ret;
+    int ret = MBEDTLS_ERR_PLATFORM_FAULT_DETECTED;
 
 #if defined(MBEDTLS_THREADING_C)
     if( ( ret = mbedtls_mutex_lock( &ctx->mutex ) ) != 0 )
@@ -344,7 +345,8 @@
 
 int mbedtls_entropy_func( void *data, unsigned char *output, size_t len )
 {
-    int ret, count = 0, i, done;
+    int ret = MBEDTLS_ERR_PLATFORM_FAULT_DETECTED;
+    int count = 0, i, done;
     mbedtls_entropy_context *ctx = (mbedtls_entropy_context *) data;
     unsigned char buf[MBEDTLS_ENTROPY_BLOCK_SIZE];
 
diff --git a/library/hmac_drbg.c b/library/hmac_drbg.c
index dd895be..d197f24 100644
--- a/library/hmac_drbg.c
+++ b/library/hmac_drbg.c
@@ -199,7 +199,7 @@
     unsigned char seed[MBEDTLS_HMAC_DRBG_MAX_SEED_INPUT];
     size_t seedlen = 0;
     size_t total_entropy_len;
-    int ret;
+    int ret = MBEDTLS_ERR_PLATFORM_FAULT_DETECTED;
 
     if( use_nonce == HMAC_NONCE_NO )
         total_entropy_len = ctx->entropy_len;
@@ -298,7 +298,7 @@
                     const unsigned char *custom,
                     size_t len )
 {
-    int ret;
+    int ret = MBEDTLS_ERR_PLATFORM_FAULT_DETECTED;
     size_t md_size;
 
     if( ( ret = mbedtls_md_setup( &ctx->md_ctx, md_info, 1 ) ) != 0 )
@@ -375,7 +375,7 @@
                                unsigned char *output, size_t out_len,
                                const unsigned char *additional, size_t add_len )
 {
-    int ret;
+    int ret = MBEDTLS_ERR_PLATFORM_FAULT_DETECTED;
     volatile unsigned char *output_fi = output;
     volatile size_t out_len_fi = out_len;
     mbedtls_hmac_drbg_context *ctx = (mbedtls_hmac_drbg_context *) p_rng;
@@ -461,7 +461,7 @@
  */
 int mbedtls_hmac_drbg_random( void *p_rng, unsigned char *output, size_t out_len )
 {
-    int ret;
+    int ret = MBEDTLS_ERR_PLATFORM_FAULT_DETECTED;
     mbedtls_hmac_drbg_context *ctx = (mbedtls_hmac_drbg_context *) p_rng;
 
 #if defined(MBEDTLS_THREADING_C)
diff --git a/library/pk.c b/library/pk.c
index caa5e17..8557513 100644
--- a/library/pk.c
+++ b/library/pk.c
@@ -576,8 +576,8 @@
                        const unsigned char *hash, size_t hash_len,
                        const unsigned char *sig, size_t sig_len )
 {
-    int ret;
-    volatile int ret_fi;
+    int ret = MBEDTLS_ERR_PLATFORM_FAULT_DETECTED;
+    volatile int ret_fi = UECC_FAULT_DETECTED;
     uint8_t signature[2*NUM_ECC_BYTES];
     unsigned char *p;
     const mbedtls_uecc_keypair *keypair = (const mbedtls_uecc_keypair *) ctx;
@@ -677,7 +677,7 @@
 static int pk_ecdsa_sig_asn1_from_uecc( unsigned char *sig, size_t *sig_len,
                                         size_t buf_len )
 {
-    int ret;
+    int ret = MBEDTLS_ERR_PLATFORM_FAULT_DETECTED;
     size_t len = 0;
     const size_t rs_len = *sig_len / 2;
     unsigned char *p = sig + buf_len;
@@ -691,10 +691,11 @@
     *--p = MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE;
     len += 2;
 
+    ret = 0;
     memmove( sig, p, len );
     *sig_len = len;
 
-    return( 0 );
+    return( ret );
 }
 
 static int uecc_eckey_sign_wrap( void *ctx, mbedtls_md_type_t md_alg,
diff --git a/library/ssl_cli.c b/library/ssl_cli.c
index 3c59923..7aee3ac 100644
--- a/library/ssl_cli.c
+++ b/library/ssl_cli.c
@@ -47,6 +47,7 @@
 #include "mbedtls/platform_time.h"
 #endif
 
+#include "mbedtls/platform.h"
 #if defined(MBEDTLS_SSL_SESSION_TICKETS)
 #include "mbedtls/platform_util.h"
 #endif
@@ -682,7 +683,7 @@
  */
 static int ssl_generate_random( mbedtls_ssl_context *ssl )
 {
-    int ret;
+    int ret = MBEDTLS_ERR_PLATFORM_FAULT_DETECTED;
     unsigned char *p = ssl->handshake->randbytes;
 #if defined(MBEDTLS_HAVE_TIME)
     mbedtls_time_t t;
@@ -2342,7 +2343,7 @@
                                          unsigned char* out,
                                          unsigned add_length_tag )
 {
-    volatile int ret = MBEDTLS_ERR_SSL_INTERNAL_ERROR;
+    volatile int ret = MBEDTLS_ERR_PLATFORM_FAULT_DETECTED;
 
     /*
      * Generate (part of) the pre-master secret as
@@ -2390,7 +2391,7 @@
                                         unsigned char *out, size_t buflen,
                                         size_t *olen )
 {
-    volatile int ret = MBEDTLS_ERR_SSL_INTERNAL_ERROR;
+    volatile int ret = MBEDTLS_ERR_PLATFORM_FAULT_DETECTED;
     size_t len_bytes = mbedtls_ssl_get_minor_ver( ssl ) ==
         MBEDTLS_SSL_MINOR_VERSION_0 ? 0 : 2;
     mbedtls_pk_context *peer_pk = NULL;
@@ -3121,7 +3122,7 @@
 
 static int ssl_process_in_server_key_exchange( mbedtls_ssl_context *ssl )
 {
-    int ret;
+    int ret = MBEDTLS_ERR_PLATFORM_FAULT_DETECTED;
     MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> parse server key exchange" ) );
 
     /* Preparation:
@@ -3362,7 +3363,7 @@
 
 static int ssl_parse_server_hello_done( mbedtls_ssl_context *ssl )
 {
-    int ret;
+    int ret = MBEDTLS_ERR_PLATFORM_FAULT_DETECTED;
 
     MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> parse server hello done" ) );
 
@@ -3396,7 +3397,7 @@
 
     MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= parse server hello done" ) );
 
-    return( 0 );
+    return( ret );
 }
 
 /*
diff --git a/library/ssl_srv.c b/library/ssl_srv.c
index bab8f00..fbad37b 100644
--- a/library/ssl_srv.c
+++ b/library/ssl_srv.c
@@ -38,6 +38,7 @@
 #include "mbedtls/debug.h"
 #include "mbedtls/ssl.h"
 #include "mbedtls/ssl_internal.h"
+#include "mbedtls/platform.h"
 #include "mbedtls/platform_util.h"
 
 #include <string.h>
@@ -3424,7 +3425,7 @@
 
 #if defined(MBEDTLS_USE_TINYCRYPT)
         {
-            int ret;
+            int ret = UECC_FAULT_DETECTED;
             static const unsigned char ecdh_param_hdr[] = {
                 MBEDTLS_SSL_EC_TLS_NAMED_CURVE,
                 0  /* high bits of secp256r1 TLS ID  */,
@@ -4213,7 +4214,7 @@
                                           unsigned char *buf,
                                           size_t buflen )
 {
-    int ret;
+    int ret = MBEDTLS_ERR_PLATFORM_FAULT_DETECTED;
     mbedtls_ssl_ciphersuite_handle_t ciphersuite_info =
         mbedtls_ssl_handshake_get_ciphersuite( ssl->handshake );
     unsigned char *p, *end;
@@ -4249,8 +4250,7 @@
         mbedtls_ssl_suite_get_key_exchange( ciphersuite_info )
         == MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA )
     {
-        ((void) ret);
-        if( mbedtls_ssl_ecdh_read_peerkey( ssl, &p, end ) != 0 )
+        if( ( ret = mbedtls_ssl_ecdh_read_peerkey( ssl, &p, end ) ) != 0 )
             return( MBEDTLS_ERR_SSL_HW_ACCEL_FAILED );
     }
     else
@@ -4272,7 +4272,6 @@
         if( ( ret = mbedtls_ecdh_read_public( &ssl->handshake->ecdh_ctx,
                                       p, end - p) ) != 0 )
         {
-            ((void) ret);
             MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ecdh_read_public", ret );
             return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE_RP );
         }
@@ -4414,7 +4413,7 @@
         return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
     }
 
-    return( 0 );
+    return( ret );
 }
 
 /* Update the handshake state */
@@ -4735,7 +4734,7 @@
  */
 int mbedtls_ssl_handshake_server_step( mbedtls_ssl_context *ssl )
 {
-    int ret = 0;
+    int ret = MBEDTLS_ERR_PLATFORM_FAULT_DETECTED;
 
     if( ssl->state == MBEDTLS_SSL_HANDSHAKE_OVER || ssl->handshake == NULL )
         return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
diff --git a/library/ssl_tls.c b/library/ssl_tls.c
index 146a8f1..b81df29 100644
--- a/library/ssl_tls.c
+++ b/library/ssl_tls.c
@@ -50,7 +50,6 @@
 #include "mbedtls/version.h"
 #include "mbedtls/platform.h"
 
-
 #include <string.h>
 
 #if defined(MBEDTLS_X509_CRT_PARSE_C)
@@ -175,7 +174,7 @@
                               unsigned char *buf,
                               size_t buflen )
 {
-    int ret = 0;
+    int ret = MBEDTLS_ERR_PLATFORM_FAULT_DETECTED;
     mbedtls_record rec;
     MBEDTLS_SSL_DEBUG_MSG( 1, ( "=> mbedtls_ssl_check_record" ) );
     MBEDTLS_SSL_DEBUG_BUF( 3, "record buffer", buf, buflen );
@@ -1892,7 +1891,7 @@
 
 int mbedtls_ssl_derive_keys( mbedtls_ssl_context *ssl )
 {
-    volatile int ret = MBEDTLS_ERR_SSL_INTERNAL_ERROR;
+    volatile int ret = MBEDTLS_ERR_PLATFORM_FAULT_DETECTED;
 
     MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> derive keys" ) );
     ssl->handshake->key_derivation_done = MBEDTLS_SSL_FI_FLAG_UNSET;
@@ -1981,7 +1980,7 @@
 
 int mbedtls_ssl_build_pms( mbedtls_ssl_context *ssl )
 {
-    volatile int ret = MBEDTLS_ERR_SSL_INTERNAL_ERROR;
+    volatile int ret = MBEDTLS_ERR_PLATFORM_FAULT_DETECTED;
 
     mbedtls_ssl_ciphersuite_handle_t ciphersuite_info =
         mbedtls_ssl_handshake_get_ciphersuite( ssl->handshake );
@@ -7319,7 +7318,7 @@
                                          void *rs_ctx )
 {
     volatile int verify_ret = MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE;
-    volatile int ret = MBEDTLS_ERR_SSL_INTERNAL_ERROR;
+    volatile int ret = MBEDTLS_ERR_PLATFORM_FAULT_DETECTED;
     volatile int flow_counter = 0;
     mbedtls_ssl_ciphersuite_handle_t ciphersuite_info =
         mbedtls_ssl_handshake_get_ciphersuite( ssl->handshake );
@@ -7945,7 +7944,7 @@
 
 int mbedtls_ssl_handshake_wrapup( mbedtls_ssl_context *ssl )
 {
-    volatile int ret = MBEDTLS_ERR_SSL_INTERNAL_ERROR;
+    volatile int ret = MBEDTLS_ERR_PLATFORM_FAULT_DETECTED;
 
 #if defined(MBEDTLS_SSL_SRV_C) && defined(MBEDTLS_SSL_SERVER_NAME_INDICATION)
     volatile const int authmode = ssl->handshake->sni_authmode != MBEDTLS_SSL_VERIFY_UNSET