diff --git a/src/packhead.cpp b/src/packhead.cpp
index eb125466..04cd51be 100644
--- a/src/packhead.cpp
+++ b/src/packhead.cpp
@@ -110,7 +110,7 @@ void PackHeader::putPackHeader(upx_bytep p)
     assert(get_le32(p) == UPX_MAGIC_LE32);
     if (get_le32(p+4) != UPX_MAGIC2_LE32)
     {
-        printf("%x %x\n", get_le32(p+4), UPX_MAGIC2_LE32);
+        //printf("%x %x\n", get_le32(p+4), UPX_MAGIC2_LE32);
         throwBadLoader();
     }
 
@@ -181,7 +181,7 @@ void PackHeader::putPackHeader(upx_bytep p)
     {
         if (p[size - 1] != old_chksum)
         {
-            printf("old_checksum: %d %d\n", p[size - 1], old_chksum);
+            //printf("old_checksum: %d %d\n", p[size - 1], old_chksum);
             throwBadLoader();
         }
     }
diff --git a/src/stub/header.ash b/src/stub/header.ash
index e0d0fea1..1b1334a1 100644
--- a/src/stub/header.ash
+++ b/src/stub/header.ash
@@ -45,13 +45,13 @@
                 dw      0               ; 16  uncompressed len
                 dw      0               ; 18  compressed len
                 db      0               ; 20  filter
-                db      0               ; 21  header checksum
+                db      45              ; 21  header checksum
  %elifdef EXE
                 db      0,0,0           ; 16  uncompressed len
                 db      0,0,0           ; 19  compressed len
                 db      0,0,0           ; 22  original file size
                 db      0               ; 25  filter
-                db      0               ; 26  header checksum
+                db      45              ; 26  header checksum
  %else
                 dd      0               ; 16  uncompressed len
                 dd      0               ; 20  compressed len