diff --git a/bitbake/lib/bb/ui/crumbs/builder.py b/bitbake/lib/bb/ui/crumbs/builder.py
index c1a75bde1a..02c9a9cb49 100755
--- a/bitbake/lib/bb/ui/crumbs/builder.py
+++ b/bitbake/lib/bb/ui/crumbs/builder.py
@@ -519,7 +519,7 @@ class Builder(gtk.Window):
             response = dialog.run()
             dialog.destroy()
         self.handler.clear_busy()
-        self.configuration.curr_mach = None
+        self.configuration.curr_mach = ""
         self.image_configuration_page.switch_machine_combo()
         self.switch_page(self.MACHINE_SELECTION)
 
@@ -868,7 +868,7 @@ class Builder(gtk.Window):
 
     def reparse_post_adv_settings(self):
         # DO reparse recipes
-        if self.configuration.curr_mach == "":
+        if not self.configuration.curr_mach:
             self.switch_page(self.MACHINE_SELECTION)
         else:
             self.switch_page(self.RCPPKGINFO_POPULATING)
diff --git a/bitbake/lib/bb/ui/crumbs/hobeventhandler.py b/bitbake/lib/bb/ui/crumbs/hobeventhandler.py
index a329380af3..3d5df9e6e6 100644
--- a/bitbake/lib/bb/ui/crumbs/hobeventhandler.py
+++ b/bitbake/lib/bb/ui/crumbs/hobeventhandler.py
@@ -256,7 +256,8 @@ class HobHandler(gobject.GObject):
         self.server.runCommand(["setVariable", "BBLAYERS", " ".join(bblayers)])
 
     def set_machine(self, machine):
-        self.server.runCommand(["setVariable", "MACHINE", machine])
+        if machine:
+            self.server.runCommand(["setVariable", "MACHINE", machine])
 
     def set_sdk_machine(self, sdk_machine):
         self.server.runCommand(["setVariable", "SDKMACHINE", sdk_machine])