diff --git a/lib/requirejs/rails/config.rb b/lib/requirejs/rails/config.rb
index 93862abf..aa039987 100644
--- a/lib/requirejs/rails/config.rb
+++ b/lib/requirejs/rails/config.rb
@@ -88,7 +88,7 @@ def initialize(application)
         uglify
         uglify2
         useStrict
-        wrap
+        wrapShim
       }
       end
 
@@ -133,6 +133,9 @@ def user_config=(cfg)
         if url = cfg.delete('baseUrl')
           raise Requirejs::ConfigError, "baseUrl is not needed or permitted in the configuration"
         end
+        # delete any cached configs, will be lazily resolved
+        self.delete(:build_config)
+        self.delete(:run_config)
         self[:user_config] = cfg
       end
 
diff --git a/lib/requirejs/rails/rjs_driver.js.erb b/lib/requirejs/rails/rjs_driver.js.erb
index f544037a..7327ad41 100644
--- a/lib/requirejs/rails/rjs_driver.js.erb
+++ b/lib/requirejs/rails/rjs_driver.js.erb
@@ -2,7 +2,7 @@ var requirejs = require(<%= rjs_path.to_s.dump %>)
 var baseConfig = <%=
 cdn_pattern = Regexp.new("\\Ahttps?://")
 
-modifiedHash = build_config.select { |k, _| k != "modules" }
+modifiedHash = build_config.select { |k, _| k != "modules" && k != "onBuildRead"}
 pathsHash = modifiedHash["paths"]
 modifiedHash["dir"] = build_dir.to_s
 modifiedHash["paths"] = Hash[
@@ -14,6 +14,10 @@ modifiedHash["paths"] = Hash[
 JSON.pretty_generate(modifiedHash)
 %>;
 
+<% if build_config["onBuildRead"] %>
+baseConfig.onBuildRead = <%= build_config["onBuildRead"] %>
+<% end %>
+
 baseConfig.modules = [
 <% build_config["modules"].each do |m| %>
   <%= JSON.pretty_generate(m) %>,