diff --git a/labsw/fw/Makefile b/labsw/fw/Makefile
index ac49633..255aaeb 100644
--- a/labsw/fw/Makefile
+++ b/labsw/fw/Makefile
@@ -28,7 +28,9 @@ USB_ID = $(shell \
 
 .PHONY:		dfu
 
-all:		io-parts.h
+all:		$(MAIN)
+
+$(MAIN).rel:	io-parts.h
 
 io-parts.h:     io.h Makefile
 		cpp -dD $< | \
@@ -45,8 +47,8 @@ io-parts.h:     io.h Makefile
 		   END { print "#endif" }' >$@ || \
 			    { rm -f $@; exit 1; }
 
-#clean::
-#		rm -f io-parts.h
+clean::
+		rm -f io-parts.h
 
 # hack: for now, we just reuse the boot loader from cntr
 USB_ID = 20b7:cb72