How to Flash Asus Zenfone 2

Preparing tools :

1. Intel USB Driver for Android ( Download Here )
2. ADB Fastboot Tool (Download Here)
3. Asus Zenfone 2 Firmware (Download Here / Here)

Steps:

1. Turn off your zenfone 2
2. Go to recovery mode (Tutorial Here)
3. Select apply update from ADB 
4. Connect your Zenfone 2 with USB Cable to your PC/laptop
5. Open command prompt in Windows (in the same folder where ADB is located)
6. Check connection by type adb devices if connection successful will be a list of zenfone 2 device
7. Type adb sideload file.zip (file.zip=adjust the filename, asus zenfone firmware that you download earlier)
8. Wait until the process is complete
9. Zenfone 2 will flash to clean thoroughly

Method 2

1. Copy Zenfone 2 Firmware to SD Card
2. Go to recovery mode (Tutorial Here)
3. Select Update via SDCard
4. Select Firmware