diff --git a/uncore/chisel-dependent.sbt b/uncore/chisel-dependent.sbt
index fa8d5490..eeb52c04 100644
--- a/uncore/chisel-dependent.sbt
+++ b/uncore/chisel-dependent.sbt
@@ -1,6 +1,6 @@
 // Provide a managed dependency on chisel if -DchiselVersion="" is
 // supplied on the command line.
 
-val chiselVersion = System.getProperty("chiselVersion", "None")
+lazy val chiselVersion = System.getProperty("chiselVersion", "None")
 
 libraryDependencies ++= ( if (chiselVersion != "None" ) ("edu.berkeley.cs" %% "chisel" % chiselVersion) :: Nil; else Nil)