diff --git a/Jamrules b/Jamrules
index 0e1e9ed930..6c6c065f9f 100644
--- a/Jamrules
+++ b/Jamrules
@@ -1526,8 +1526,8 @@ rule UnarchiveObjects
 
 actions UnarchiveObjects
 {
-	cd `dirname $(1[1])`
-	ar -x "$(2)" $(1)
+	cd $(1[1]:D)
+	ar -x "$(2)" $(1:B).o
 	cd -
 }