diff --git a/wolfcrypt/src/tfm.c b/wolfcrypt/src/tfm.c
index 021928d6e..c45fa6dee 100755
--- a/wolfcrypt/src/tfm.c
+++ b/wolfcrypt/src/tfm.c
@@ -1057,7 +1057,8 @@ static int _fp_exptmod(fp_int * G, fp_int * X, fp_int * P, fp_int * Y)
   }
 
   /* init M array */
-  XMEMSET(M, 0, sizeof(M));
+  for(x = 0; x < (int)(sizeof(M)/sizeof(fp_int)); x++)
+    fp_init(&M[x]);
 
   /* now setup montgomery  */
   if ((err = fp_montgomery_setup (P, &mp)) != FP_OKAY) {
@@ -1456,6 +1457,10 @@ int fp_cmp(fp_int *a, fp_int *b)
 /* compare against a single digit */
 int fp_cmp_d(fp_int *a, fp_digit b)
 {
+  /* special case for zero*/
+  if (a->used == 0 && b == 0)
+    return FP_EQ;
+
   /* compare based on sign */
   if ((b && a->used == 0) || a->sign == FP_NEG) {
     return FP_LT;
@@ -2156,9 +2161,10 @@ int mp_div_2d(fp_int* a, int b, fp_int* c, fp_int* d)
 #ifdef ALT_ECC_SIZE
 void fp_copy(fp_int *a, fp_int* b)
 {
-    if (a != b) {
+    if (a != b && b->size >= a->used) {
         b->used = a->used;
         b->sign = a->sign;
+
         XMEMCPY(b->dp, a->dp, a->used * sizeof(fp_digit));
     }
 }