Fix software compilation

flows/makefile.software

@@ -169,7 +169,7 @@ compile_all_code: bootrom debugtester
 	  echo Removing old image.hex ;\
 	  rm -f image.hex  ;\
 	  $(MAKE) testcode TESTNAME=$$thistest;\
-	  if [ -e $(SIM_DIR)/$$thistest/image.hex ] ; then \
+	  if [ -e $(SIM_TOP_DIR)/$$thistest/image.hex ] ; then \
             echo OK    - image.hex     created for test $$thistest ;\
 	  else \
 	    echo ERROR - image.hex NOT created for test $$thistest ;\