diff --git a/tools/mfd_aes_brute/brute_key.c b/tools/mfd_aes_brute/brute_key.c
index 654fed6c6..e02a597e2 100644
--- a/tools/mfd_aes_brute/brute_key.c
+++ b/tools/mfd_aes_brute/brute_key.c
@@ -112,7 +112,7 @@ int main(int argc, char *argv[]) {
     uint8_t lock_challenge[32] = {0x00};
 
     uint64_t timestamp = 0;
-    sscanf(argv[1], "%lu", &timestamp);
+    sscanf(argv[1], "%"PRIu64, &timestamp);
 
     if (argc != 4) {
         printf("\nusage: %s <unix timestamp> <16 byte tag challenge> <32 byte lock challenge>\n\n", argv[0]);
diff --git a/tools/mfd_aes_brute/mfd_aes_brute.c b/tools/mfd_aes_brute/mfd_aes_brute.c
index 4eba06051..b92eee31c 100644
--- a/tools/mfd_aes_brute/mfd_aes_brute.c
+++ b/tools/mfd_aes_brute/mfd_aes_brute.c
@@ -234,7 +234,7 @@ int main(int argc, char *argv[]) {
     if (argc != 4) return usage(argv[0]);
 
     uint64_t start_time = 0;
-    sscanf(argv[1], "%lu", &start_time);
+    sscanf(argv[1], "%"PRIu64, &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 bbd213a35..4279fba62 100644
--- a/tools/mfd_aes_brute/mfd_multi_brute.c
+++ b/tools/mfd_aes_brute/mfd_multi_brute.c
@@ -379,7 +379,7 @@ int main(int argc, char *argv[]) {
     }
 
     uint64_t start_time = 0;
-    sscanf(argv[3], "%lu", &start_time);
+    sscanf(argv[3], "%"PRIu64, &start_time);
 
     printf("Crypto algo............ " _GREEN_("%s") "\n", algostr);
     printf("LCR Random generator... " _GREEN_("%s") "\n", generators[g_idx].Name);