diff --git a/b2g/build.mk b/b2g/build.mk
index 644dadc270913..da970e7245a3e 100644
--- a/b2g/build.mk
+++ b/b2g/build.mk
@@ -11,8 +11,11 @@ package:
 	@$(MAKE) -C b2g/installer
 
 install::
-	@echo 'B2G can't be installed directly.'
-	@exit 1
+	@adb shell stop b2g
+	@adb remount
+	@adb shell rm -rf /system/b2g
+	@adb push dist/b2g/ /system/b2g
+	@adb shell start b2g
 
 upload::
 	@$(MAKE) -C b2g/installer upload
diff --git a/python/mozbuild/mozbuild/base.py b/python/mozbuild/mozbuild/base.py
index b11c9f22751c1..97f75e98af4b4 100644
--- a/python/mozbuild/mozbuild/base.py
+++ b/python/mozbuild/mozbuild/base.py
@@ -1010,11 +1010,21 @@ def is_b2g_desktop(cls):
                     (cls.substs.get('MOZ_WIDGET_TOOLKIT') != 'gonk'))
         return False
 
+    @staticmethod
+    def is_b2g(cls):
+        """Must have a B2G build."""
+        if hasattr(cls, 'substs'):
+            return ((cls.substs.get('MOZ_BUILD_APP') == 'b2g') and
+                    (cls.substs.get('MOZ_WIDGET_TOOLKIT') == 'gonk'))
+        return False
+
+
     @staticmethod
     def has_build(cls):
         """Must have a build."""
         return (MachCommandConditions.is_firefox_or_android(cls) or
                 MachCommandConditions.is_thunderbird(cls) or
+                MachCommandConditions.is_b2g(cls) or
                 MachCommandConditions.is_b2g_desktop(cls))
 
     @staticmethod