diff --git a/copy-firmware.sh b/copy-firmware.sh
index 148f0f19..20746a47 100755
--- a/copy-firmware.sh
+++ b/copy-firmware.sh
@@ -44,6 +44,14 @@ while test $# -gt 0; do
             shift
             ;;
 
+        -*)
+            if test "$compress" = "cat"; then
+                echo "ERROR: unknown command-line option: $1"
+                exit 1
+            fi
+            compress="$compress $1"
+            shift
+            ;;
         *)
             if test "x$destdir" != "x"; then
                 echo "ERROR: unknown command-line options: $*"