diff --git a/py/mkrules.mk b/py/mkrules.mk
index 6993a13a4f..4968ed58b0 100644
--- a/py/mkrules.mk
+++ b/py/mkrules.mk
@@ -108,6 +108,10 @@ $(BUILD)/%.pp: %.c FORCE
 	$(ECHO) "PreProcess $<"
 	$(Q)$(CPP) $(CFLAGS) -Wp,-C,-dD,-dI -o $@ $<
 
+.PHONY: $(BUILD)/%.sz
+$(BUILD)/%.sz: $(BUILD)/%.o
+	$(Q)$(SIZE) $<
+
 # Special case for compiling auto-generated source files.
 $(BUILD)/%.o: $(BUILD)/%.c
 	$(call compile_c)