diff --git a/tools/mfc/card_only/staticnested_1nt.c b/tools/mfc/card_only/staticnested_1nt.c
index afd839ad6..e2dc13277 100644
--- a/tools/mfc/card_only/staticnested_1nt.c
+++ b/tools/mfc/card_only/staticnested_1nt.c
@@ -51,7 +51,8 @@ static int bin_to_uint8_arr(const char *bin_str, uint8_t bit_arr[], uint8_t arr_
 }
 
 static uint64_t *generate_keys(uint64_t authuid, uint32_t nt, uint32_t nt_enc, uint32_t nt_par_enc, uint32_t *keyCount) {
-    uint64_t *result_keys = (uint64_t *)malloc(KEY_SPACE_SIZE * sizeof(uint64_t));
+
+    uint64_t *result_keys = (uint64_t *)calloc(1, KEY_SPACE_SIZE * sizeof(uint64_t));
     if (result_keys == NULL) {
         fprintf(stderr, "\nMalloc error in generate_and_intersect_keys!\n");
         return NULL;
@@ -67,9 +68,9 @@ static uint64_t *generate_keys(uint64_t authuid, uint32_t nt, uint32_t nt_enc, u
         free(result_keys);
         return NULL;
     }
-    if (revstate_start == NULL) {
-        revstate_start = revstate;
-    }
+
+    revstate_start = revstate;
+
     s = crypto1_create(0);
     if (s == NULL) {
         fprintf(stderr, "\nMalloc error in generate_keys!\n");
@@ -77,6 +78,7 @@ static uint64_t *generate_keys(uint64_t authuid, uint32_t nt, uint32_t nt_enc, u
         crypto1_destroy(revstate_start);
         return 0;
     }
+
     while ((revstate->odd != 0x0) || (revstate->even != 0x0)) {
         lfsr_rollback_word(revstate, nt ^ authuid, 0);
         crypto1_get_lfsr(revstate, &lfsr);
@@ -99,6 +101,7 @@ static uint64_t *generate_keys(uint64_t authuid, uint32_t nt, uint32_t nt_enc, u
         }
         revstate++;
     }
+
     crypto1_destroy(s);
     crypto1_destroy(revstate_start);
     revstate_start = NULL;
@@ -140,11 +143,11 @@ int main(int argc, char *const argv[]) {
 
     printf("Finding key candidates...\n");
     keys = generate_keys(authuid, nt, nt_enc, nt_par_enc, &keyCount);
-    printf("Finding phase complete, found %i keys\n", keyCount);
+    printf("Finding phase complete, found %u keys\n", keyCount);
 
     FILE *fptr;
     char filename[30];
-    snprintf(filename, sizeof(filename), "keys_%08x_%02i_%08x.dic", authuid, sector, nt);
+    snprintf(filename, sizeof(filename), "keys_%08x_%02u_%08x.dic", authuid, sector, nt);
 
     fptr = fopen(filename, "w");
     if (fptr != NULL) {