diff --git a/pharo/GNUmakefile b/pharo/GNUmakefile
index a567741..b685cea 100644
--- a/pharo/GNUmakefile
+++ b/pharo/GNUmakefile
@@ -71,7 +71,7 @@ prereq::
 
 $(PROJECT).image: ../src/*/*.st
 	$(call pharo-copy-image, $(PHARO_IMAGE), $@)
-	$(call pharo-load-local, $@, MachineArithmetic,$(MACHINEARITHMETIC_DIR))
+	$(call pharo-load-local, $@, MachineArithmetic,$(MACHINEARITHMETIC_DIR)/src)
 	$(call pharo-load-local, $@, ArchC,            $(ARCHC_DIR)/src)
 	$(call pharo-load-local, $@, SmallRSP,         $(SMALLRSP_DIR)/src)
 	$(call pharo-load-local, $@, LibUnix,          $(PHARO_HACKS_DIR)/src)