The Android 6.0.1 Marshmallow update for the ASUS ZenFone Selfie (Z00UD) brings several enhancements and new features, including:
Always download firmware intended for the WW (Worldwide) SKU. Flashing a CN (China) or TW (Taiwan) SKU on a WW device can result in a soft brick. The file name should look like: UL-Z00UD-WW-xx.x.x.xxx-user.zip . asus zenfone selfie z00ud firmware 6.0 1