diff --git a/rocket/chisel-dependent.sbt b/rocket/chisel-dependent.sbt
index e784e5e9..c65c7811 100644
--- a/rocket/chisel-dependent.sbt
+++ b/rocket/chisel-dependent.sbt
@@ -1,7 +1,7 @@
 // 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