diff --git a/tool/ports/mk/hash.inc b/tool/ports/mk/hash.inc
index d26ffca048..f3e2838e12 100644
--- a/tool/ports/mk/hash.inc
+++ b/tool/ports/mk/hash.inc
@@ -17,6 +17,8 @@
 
 $(call check_tool,sha1sum)
 
+REDIR ?= > $@
+
 _PATCHES_IN_REP_DIR := $(foreach P,$(PATCHES),\
                          $(wildcard $(REP_DIR)/$(subst $(REP_DIR)/,,$(P))))
 
@@ -27,7 +29,7 @@ endif
 
 $(_DST_HASH_FILE): $(HASH_INPUT) $(MAKEFILE_LIST)
 	@$(MSG_GENERATE)$(notdir $@)
-	$(VERBOSE)cat $(HASH_INPUT) | sha1sum | sed "s/ .*//" > $@
+	$(VERBOSE)cat $(HASH_INPUT) | sha1sum | sed "s/ .*//" $(REDIR)
 
 _check_hash: $(_DST_HASH_FILE)
 ifneq ($(CHECK_HASH),no)
diff --git a/tool/ports/mk/install.mk b/tool/ports/mk/install.mk
index 69dc6cb25e..77d9e24fe5 100644
--- a/tool/ports/mk/install.mk
+++ b/tool/ports/mk/install.mk
@@ -20,6 +20,8 @@
 # XXX remove this line when the tool has stabilized
 STRICT_HASH ?= no
 
+PORTS_TOOL_DIR ?= $(GENODE_DIR)/tool/ports
+
 #
 # Utility to check if a python module is installed
 #
@@ -45,7 +47,7 @@ _prefer = $(if $1,$1,$2)
 #
 # Include common definitions
 #
-include $(GENODE_DIR)/tool/ports/mk/common.inc
+include $(PORTS_TOOL_DIR)/mk/common.inc
 
 #
 # Include definitions provided by the port description file
@@ -87,7 +89,7 @@ _dirs: $(DOWNLOADS)
 ## Generate the HASH file
 ##
 
-include $(GENODE_DIR)/tool/ports/mk/hash.inc
+include $(PORTS_TOOL_DIR)/mk/hash.inc
 
 
 ##