diff --git a/tools/mfd_aes_brute/brute_key.c b/tools/mfd_aes_brute/brute_key.c
index 41c91f3c7..654fed6c6 100644
--- a/tools/mfd_aes_brute/brute_key.c
+++ b/tools/mfd_aes_brute/brute_key.c
@@ -111,7 +111,8 @@ int main(int argc, char *argv[]) {
     uint8_t tag_challenge[16]  = {0x00};
     uint8_t lock_challenge[32] = {0x00};
 
-    uint64_t timestamp = atoi(argv[1]);
+    uint64_t timestamp = 0;
+    sscanf(argv[1], "%lu", &timestamp);
 
     if (argc != 4) {
         printf("\nusage: %s <unix timestamp> <16 byte tag challenge> <32 byte lock challenge>\n\n", argv[0]);
@@ -124,8 +125,10 @@ int main(int argc, char *argv[]) {
     if (hexstr_to_byte_array(argv[3], lock_challenge, sizeof(lock_challenge)))
         return 3;
 
+    // current time
     uint64_t start_time = time(NULL);
 
+    // from a time before up until current time.
     for (; timestamp < start_time; timestamp++) {
 
         make_key(timestamp, key);
diff --git a/tools/mfd_aes_brute/mfd_aes_brute.c b/tools/mfd_aes_brute/mfd_aes_brute.c
index d4bca2bb8..4eba06051 100644
--- a/tools/mfd_aes_brute/mfd_aes_brute.c
+++ b/tools/mfd_aes_brute/mfd_aes_brute.c
@@ -233,7 +233,8 @@ int main(int argc, char *argv[]) {
 
     if (argc != 4) return usage(argv[0]);
 
-    uint64_t start_time = atoi(argv[1]);
+    uint64_t start_time = 0;
+    sscanf(argv[1], "%lu", &start_time);
 
     uint8_t tag_challenge[16] = {0x00};
     if (hexstr_to_byte_array(argv[2], tag_challenge, sizeof(tag_challenge)))
diff --git a/tools/mfd_aes_brute/mfd_multi_brute.c b/tools/mfd_aes_brute/mfd_multi_brute.c
index 704796255..bbd213a35 100644
--- a/tools/mfd_aes_brute/mfd_multi_brute.c
+++ b/tools/mfd_aes_brute/mfd_multi_brute.c
@@ -172,7 +172,7 @@ static void print_time(uint64_t at) {
     char res[32];
     strftime(res, sizeof(res), "%Y-%m-%d %H:%M:%S", &lt);
 
-    printf("%u  ( '%s' )\n", (unsigned)t, res);
+    printf("%"PRIu64" ( '%s' )\n", t, res);
 }
 
 static void *brute_thread(void *arguments) {
@@ -378,7 +378,8 @@ int main(int argc, char *argv[]) {
         return 1;
     }
 
-    uint64_t start_time = atoi(argv[3]);
+    uint64_t start_time = 0;
+    sscanf(argv[3], "%lu", &start_time);
 
     printf("Crypto algo............ " _GREEN_("%s") "\n", algostr);
     printf("LCR Random generator... " _GREEN_("%s") "\n", generators[g_idx].Name);