diff --git a/programs/system/open/Tupfile.lua b/programs/system/open/Tupfile.lua
index 1daa219a24..c6389cd8ed 100644
--- a/programs/system/open/Tupfile.lua
+++ b/programs/system/open/Tupfile.lua
@@ -1,3 +1,3 @@
 if tup.getconfig("NO_FASM") ~= "" then return end
 tup.rule("echo lang fix " .. ((tup.getconfig("LANG") == "") and "en" or tup.getconfig("LANG")) .. " > lang.inc", {"lang.inc"})
-tup.rule("open.asm", "fasm %f %o " .. tup.getconfig("KPACK_CMD"), "open")
\ No newline at end of file
+tup.rule({"open.asm", extra_inputs = {"lang.inc"}}, "fasm %f %o " .. tup.getconfig("KPACK_CMD"), "open")