diff --git a/build_boot9strap_firm.py b/build_boot9strap_firm.py
index 0dc6477..d402fb3 100644
--- a/build_boot9strap_firm.py
+++ b/build_boot9strap_firm.py
@@ -18,7 +18,9 @@ def main(argc, argv):
         b9s.write(b'FIRM')
         # Write (zero (boot priority)), ARM11 Entrypoint, ARM9 Entrypoint
         b9s.write(struct.pack('<III', 0x00000000, 0x1FF80200, 0x08001000))
-        b9s.write(b'\x00' * 0x2D)
+        b9s.write(b'\x00' * 0x2C)
+        # Write version value
+        b9s.write(b'\x01')
         # Write boot9strap magic value
         b9s.write(b'B9S')
         ofs = 0x200