[ROM][Full Firmware] ASUS ZenFone 2 ZE551ML Marshmallow WW-4.21.40.223

How to OTA update ? (Go to settings>About>System Update>Check for Update)
How to update Manual ? Place to Internal Storage>Restart>Click Update
How to update via ADB sideload ? Here

ZENFONE 2 ZE551ML firmware:

WW VERSION
WW-4.21.40.223

Description	ASUS ZenFone 2=ZE551ML(Z00AD/Z00ADA/Z00ADB/Z00ADC) software Image: V4.21.40.223 for WW SKU only* (andriod M) Improvement Item: 1)Improve Wi-Fi/Bluetooth stability 2)Update Security patch 3)Improve system stability 4)Support India SOS call (India only) Steps of Update: 1.Check software version of your device** 2.Download device software and Update SOP (From “Manual” Item) 3.Only apply to same SKU update, Example: WW->WW, CN->CN, . 4.Software update cannot transfer the software SKU and downgrade the software version. 5.Wrong SKU may cause update failure, please update the same SKU version only. How to know the device model? Path: Settings->About-> Model number Example: ASUS_T00I How to know the device software version? Path: Settings->About-> software information->Build number **System upgrade may cause part of data missing, please buckup your important data before system upgrading.

Description

ASUS ZenFone 2=ZE551ML(Z00AD/Z00ADA/Z00ADB/Z00ADC) software Image: V4.21.40.223 for WW SKU only* (andriod M)
Improvement Item:
1)Improve Wi-Fi/Bluetooth stability
2)Update Security patch
3)Improve system stability
4)Support India SOS call (India only)

Steps of Update:
1.Check software version of your device**
2.Download device software and Update SOP (From “Manual” Item)
3.Only apply to same SKU update, Example: WW->WW, CN->CN, .
4.Software update cannot transfer the software SKU and downgrade the software version.
5.Wrong SKU may cause update failure, please update the same SKU version only.

*How to know the device model?
Path: Settings->About-> Model number
Example: ASUS_T00I
**How to know the device software version?
Path: Settings->About-> software information->Build number
***System upgrade may cause part of data missing, please buckup your important data before system upgrading.

File Size	1.18 GB 2017.01.10 update
Download from	Global