diff --git a/build/pack.sh b/build/pack.sh
index c15f4a0..2083137 100755
--- a/build/pack.sh
+++ b/build/pack.sh
@@ -10,7 +10,8 @@
 #  +   ▀████████████████████████████████████████████████████▀
 #
 # A script to package release binaries + README.md into zip files.
-# Usage: cd outfly; build/pack.sh
+# Usage: cd outfly; build/pack.sh [-b]
+# Options: -b: cross-compile targets before packing
 
 set -e