diff --git a/Jamrules b/Jamrules
index 474180e835..efb4676347 100644
--- a/Jamrules
+++ b/Jamrules
@@ -1607,7 +1607,7 @@ rule UnarchiveObjects
 actions UnarchiveObjects
 {
 	cd $(1[1]:D)
-	ar -x "$(2)" $(1:B).o
+	ar -x "$(2)" $(1:D=)
 	cd -
 }