diff --git a/libnfc_crypto1_crack.c b/libnfc_crypto1_crack.c
index 1b41542..2015dcb 100755
--- a/libnfc_crypto1_crack.c
+++ b/libnfc_crypto1_crack.c
@@ -640,7 +640,7 @@ int main (int argc, const char * argv[]) {
     }
     
     char filename[21];
-    sprintf(filename, "0x%04x_%03u%s.txt", uid, target_block, target_key == MC_AUTH_A ? "A" : "B");
+    sprintf(filename, "0x%08x_%03u%s.txt", uid, target_block, target_key == MC_AUTH_A ? "A" : "B");
     fp = fopen(filename, "wb");
 
     printf("Found tag with uid %04x, collecting nonces for key %s of block %u (sector %u) using known key %s %012"PRIx64" for block %u (sector %u)\n",
diff --git a/txttobin.py b/txttobin.py
index 670e9ed..ac53400 100644
--- a/txttobin.py
+++ b/txttobin.py
@@ -1,6 +1,7 @@
 import sys
 data = file(sys.argv[1], 'rb').readlines()
-uid = sys.argv[1].replace('.txt','')
+if sys.argv[1].endswith('.txt'):
+    uid = sys.argv[1][:-4]
 
 def parity(x):
     return ("{0:08b}".format(x).count('1') & 1)