diff --git a/Makefile b/Makefile
index 5537086c6a..8ca30a80ec 100644
--- a/Makefile
+++ b/Makefile
@@ -120,40 +120,40 @@ usb_lib:
 $(MESSAGES_H) : $(MESSAGES_XML) $(CONF_XML) tools
 	$(Q)test -d $(STATICINCLUDE) || mkdir -p $(STATICINCLUDE)
 	@echo BUILD $@
-	$(Q)PAPARAZZI_SRC=$(PAPARAZZI_SRC) $(TOOLS)/gen_messages.out $< telemetry > /tmp/msg.h
+	$(Q)PAPARAZZI_SRC=$(PAPARAZZI_SRC) PAPARAZZI_HOME=$(PAPARAZZI_HOME) $(TOOLS)/gen_messages.out $< telemetry > /tmp/msg.h
 	$(Q)mv /tmp/msg.h $@
 	$(Q)chmod a+r $@
 
 $(MESSAGES2_H) : $(MESSAGES_XML) $(CONF_XML) tools
 	$(Q)test -d $(STATICINCLUDE) || mkdir -p $(STATICINCLUDE)
 	@echo BUILD $@
-	$(Q)PAPARAZZI_SRC=$(PAPARAZZI_SRC) $(TOOLS)/gen_messages2.out $< telemetry > /tmp/msg2.h
+	$(Q)PAPARAZZI_SRC=$(PAPARAZZI_SRC) PAPARAZZI_HOME=$(PAPARAZZI_HOME) $(TOOLS)/gen_messages2.out $< telemetry > /tmp/msg2.h
 	$(Q)mv /tmp/msg2.h $@
 	$(Q)chmod a+r $@
 
 $(UBX_PROTOCOL_H) : $(UBX_XML) tools
 	@echo BUILD $@
-	$(Q)PAPARAZZI_SRC=$(PAPARAZZI_SRC) $(TOOLS)/gen_ubx.out $< > /tmp/ubx.h
+	$(Q)PAPARAZZI_SRC=$(PAPARAZZI_SRC) PAPARAZZI_HOME=$(PAPARAZZI_HOME) $(TOOLS)/gen_ubx.out $< > /tmp/ubx.h
 	$(Q)mv /tmp/ubx.h $@
 
 $(MTK_PROTOCOL_H) : $(MTK_XML) tools
 	@echo BUILD $@
-	$(Q)PAPARAZZI_SRC=$(PAPARAZZI_SRC) $(TOOLS)/gen_mtk.out $< > /tmp/mtk.h
+	$(Q)PAPARAZZI_SRC=$(PAPARAZZI_SRC) PAPARAZZI_HOME=$(PAPARAZZI_HOME) $(TOOLS)/gen_mtk.out $< > /tmp/mtk.h
 	$(Q)mv /tmp/mtk.h $@
 
 $(XSENS_PROTOCOL_H) : $(XSENS_XML) tools
 	@echo BUILD $@
-	$(Q)PAPARAZZI_SRC=$(PAPARAZZI_SRC) $(TOOLS)/gen_xsens.out $< > /tmp/xsens.h
+	$(Q)PAPARAZZI_SRC=$(PAPARAZZI_SRC) PAPARAZZI_HOME=$(PAPARAZZI_HOME) $(TOOLS)/gen_xsens.out $< > /tmp/xsens.h
 	$(Q)mv /tmp/xsens.h $@
 
 $(DL_PROTOCOL_H) : $(MESSAGES_XML) tools
 	@echo BUILD $@
-	$(Q)PAPARAZZI_SRC=$(PAPARAZZI_SRC) $(TOOLS)/gen_messages.out $< datalink > /tmp/dl.h
+	$(Q)PAPARAZZI_SRC=$(PAPARAZZI_SRC) PAPARAZZI_HOME=$(PAPARAZZI_HOME) $(TOOLS)/gen_messages.out $< datalink > /tmp/dl.h
 	$(Q)mv /tmp/dl.h $@
 
 $(DL_PROTOCOL2_H) : $(MESSAGES_XML) tools
 	@echo BUILD $@
-	$(Q)PAPARAZZI_SRC=$(PAPARAZZI_SRC) $(TOOLS)/gen_messages2.out $< datalink > /tmp/dl2.h
+	$(Q)PAPARAZZI_SRC=$(PAPARAZZI_SRC) PAPARAZZI_HOME=$(PAPARAZZI_HOME) $(TOOLS)/gen_messages2.out $< datalink > /tmp/dl2.h
 	$(Q)mv /tmp/dl2.h $@
 
 include Makefile.ac