diff --git a/wolfcrypt/src/tfm.c b/wolfcrypt/src/tfm.c
index 6e3d2fe8b..373c9e85c 100644
--- a/wolfcrypt/src/tfm.c
+++ b/wolfcrypt/src/tfm.c
@@ -4051,12 +4051,16 @@ int fp_read_unsigned_bin(fp_int *a, const unsigned char *b, int c)
   /* zero the int */
   fp_zero (a);
 
+  if (c < 0) {
+      return FP_VAL;
+  }
+
   if (c == 0) {
       return FP_OKAY;
   }
 
   /* if input b excess max, then truncate */
-  if (c > 0 && (word32)c > maxC) {
+  if ((word32)c > maxC) {
      int excess = (c - maxC);
      c -= excess;
      b += excess;
diff --git a/wolfcrypt/test/test.c b/wolfcrypt/test/test.c
index 534dedc43..6b802e356 100644
--- a/wolfcrypt/test/test.c
+++ b/wolfcrypt/test/test.c
@@ -16930,7 +16930,7 @@ static wc_test_ret_t rsa_decode_test(RsaKey* keyPub)
         goto done;
     }
     ret = wc_RsaPublicKeyDecodeRaw(n, (word32)-1, e, sizeof(e), keyPub);
-#if !defined(WOLFSSL_SP_MATH) & !defined(WOLFSSL_SP_MATH_ALL)
+#if defined(USE_INTEGER_HEAP_MATH)
     if (ret != 0)
 #else
     if (ret != ASN_GETINT_E)
@@ -16944,11 +16944,12 @@ static wc_test_ret_t rsa_decode_test(RsaKey* keyPub)
     if (ret != 0)
         return WC_TEST_RET_ENC_EC(ret);
     ret = wc_RsaPublicKeyDecodeRaw(n, sizeof(n), e, (word32)-1, keyPub);
-#if !defined(WOLFSSL_SP_MATH) & !defined(WOLFSSL_SP_MATH_ALL)
-    if (ret != 0) {
+#if defined(USE_INTEGER_HEAP_MATH)
+    if (ret != 0)
 #else
-    if (ret != ASN_GETINT_E) {
+    if (ret != ASN_GETINT_E)
 #endif
+    {
         ret = WC_TEST_RET_ENC_EC(ret);
         goto done;
     }