The official Android 6.0.1 Marshmallow firmware for the ASUS ZenFone Selfie (Z00UD / ZD551KL)
is primarily identified by build number WW_21.40.0.1692. This update marked the final major OS transition for the device, transitioning it from Android 5.0 Lollipop to Marshmallow. Key Firmware Highlights
The update introduced standard Marshmallow features while significantly streamlining the ZenUI interface: asus zenfone selfie z00ud firmware 6.0 1
Performance Optimizations: Includes Doze Mode for improved battery life and a new App Permissions system for better privacy control.
Bloatware Removal: ASUS removed over 15 pre-loaded "bloatware" apps to free up internal storage and improve system speed. Removed apps include ASUS Backup, Mirror, Remote Link, PC Link, and Omlet. The official Android 6
App Replacements: Standard ZenUI apps like ASUS Email, Calendar, and Messaging were replaced by official Google alternatives (Gmail, Google Calendar, and Google Messenger) after a factory reset.
New Features: Added Motion Gestures, Pano Sphere Mode for the camera, and updated emojis. Q2: Will this firmware lock my bootloader
Storage Warning: The APP2SD feature is no longer supported in Android 6.0; users must move apps to internal storage before upgrading to avoid data loss. Installation Methods Users can update their ZenFone Selfie Go to product viewer dialog for this item. through two primary methods: 1. Over-the-Air (OTA) Update
This is the easiest method if the update is still being pushed to your region:
No, it will not relock an unlocked bootloader. But to flash official OTAs later, you need a locked bootloader.
If you lack an SD card, use ADB:
adb sideload UL-Z00D-WW-22.40.0.59-user.zip