diff --git a/NEWS b/NEWS
index 21cd9e7c..1da917ce 100644
--- a/NEWS
+++ b/NEWS
@@ -1,3 +1,5 @@
+* #3025: Make bundlebuilder work even if SUGAR_PREFIX is not set. (marco)
+
 Snapshot 0b3f687749
 
 * #3088: Fix style of zoom buttons palettes. (marco)
diff --git a/services/shell/bundleregistry.py b/services/shell/bundleregistry.py
index 19d00328..fbcef878 100644
--- a/services/shell/bundleregistry.py
+++ b/services/shell/bundleregistry.py
@@ -56,7 +56,7 @@ class _ServiceManager(object):
 
     def add(self, bundle):
         util.write_service(bundle.get_service_name(),
-                           bundle.get_exec(), self._path)
+                           bundle.get_command(), self._path)
 
 class BundleRegistry(gobject.GObject):
     """Service that tracks the available activity bundles"""
diff --git a/sugar/activity/activityfactoryservice.py b/sugar/activity/activityfactoryservice.py
index 63265a13..682abaa0 100644
--- a/sugar/activity/activityfactoryservice.py
+++ b/sugar/activity/activityfactoryservice.py
@@ -163,4 +163,4 @@ def run(bundle_path):
     _sugarext.set_application_name(bundle.get_name())
 
     factory = ActivityFactoryService(bundle.get_service_name(),
-                                     bundle.get_class())
+                                     bundle.activity_class)
diff --git a/sugar/activity/bundle.py b/sugar/activity/bundle.py
index 8bf33866..cccff5ae 100644
--- a/sugar/activity/bundle.py
+++ b/sugar/activity/bundle.py
@@ -59,6 +59,9 @@ class Bundle:
         self._init_with_path(path)
 
     def _init_with_path(self, path):
+        self.activity_class = None
+        self.bundle_exec = None
+
         self._name = None
         self._icon = None
         self._service_name = None
@@ -116,18 +119,10 @@ class Bundle:
             logging.error('%s must specify a name' % self._path)
 
         if cp.has_option(section, 'class'):
-            self._class = cp.get(section, 'class')
-            self._exec = '%s --bundle-path="%s"' % (
-              env.get_bin_path(_PYTHON_FACTORY), self._path)
+            self.activity_class = cp.get(section, 'class')
         elif cp.has_option(section, 'exec'):
-            self._class = None
-            cmdline = cp.get(section, 'exec')
-            cmdline = os.path.join(self._path, cmdline)
-            cmdline = cmdline.replace('$SUGAR_BUNDLE_PATH', self._path) 
-            cmdline = os.path.expandvars(cmdline)
-            self._exec = cmdline
+            self.bundle_exec = cp.get(section, 'exec')
         else:
-            self._exec = None
             self._valid = False
             logging.error('%s must specify exec or class' % self._path)
 
@@ -232,9 +227,17 @@ class Bundle:
         """Get the activity version"""
         return self._activity_version
 
-    def get_exec(self):
+    def get_command(self):
         """Get the command to execute to launch the activity factory"""
-        return self._exec
+        if self.bundle_exec:
+            command = os.path.join(self._path, self.bundle_exec)
+            command = command.replace('$SUGAR_BUNDLE_PATH', self._path)
+            command = os.path.expandvars(command)
+        else:
+            command = '%s --bundle-path="%s"' % (
+                  env.get_bin_path(_PYTHON_FACTORY), self._path)
+
+        return command
 
     def get_class(self):
         """Get the main Activity class"""