[ASUS ZenFone 6 (2019) Guides, News, & Discussion] _Kuroi_:
Hello.

This guide will help you unbrick your device in case your devices hangs as it boots, and always boots into fastboot mode and recovery is unavailable and the like.

Note: Unlocked bootloader is not required to do any of the actions described in this guide.

Disclaimer: I'm in no way responsible for the actions you perform and whatever happens to your device due to these actions. Proceed at your own risk.

Prerequisites:

Service firmware. Can be downloaded here. It's an older build, but it will do the trick and it's the only one I could find freely available at the time of writing. Only for WW SKU

Zip for your desired build. Can be found here.

- Note: For this guide, my desired build will be WW-17.1810.1910.63, which is a special case, as you will need to flash in the following order: Service Firmware -> WW-16.1220.1909.194 -> WW-17.1810.1910.63. In other cases, unless noted otherwise in a description of the build on the ASUS website, Service Firmware -> Desired build will suffice.

Platform tools of Android SDK. Latest package can be downloaded from: Windows | Linux. Somewhat optional but good to have.

Step 1 - Preparing the environment

This is not required but for the sake of simplicity and keeping everything in one place, create a folder and name it whatever you like, for example ASUS or Unbrick

Create a sub-folder inside the folder you've created in the previous step, call it service_firmware, download and unzip service firmware into this folder

Download files for the desired builds from the above link. For this specific case, WW-16.1220.1909.194 and WW-17.1810.1910.63.

3.a If you have microSD card, transfer zip file for the desired build into its root and insert the card into the phone.

3.b. If you do not have a microSD card, download and unzip platform tools mentioned in the prerequisites as you will need adb to flash firmware/s via sideload

Step 2 - Flashing service firmware

Connect your phone via USB

Enter fastboot mode via one of the methods:

1.1. Turn off your device, then turn it on while holding down the power and volume up buttons at the same time. Release the power button when it powers up (keep holding the volume up button)

1.2. If you have platform tools, you can do adb reboot fastboot

Open CMD (windows) | Terminal (unix)

CD into the folder with service firmware from item #2 from the step above.

Make sure your phone is detected by typing fastboot devices

Ensure battery is at

least 20%

charged. Aside from normal means, it's possible to check the battery charge via fastboot oem get-batcap.

Sample output: (bootloader) bat cap = 35, which means that the battery is 35% charged.

IMPORTANT NOTE BEFORE CONTINUING:

By default

, flashing with one of the scripts

wipes your userdata

, in other words, it performs a factory reset.

It is possible to avoid userdata wipe

(

although not encouraged

) but keep in mind,

unless you flash your current build after flashing service firmware, your phone will not boot up.

If you absolutely would like to preserve your userdata, even if for the sake of backing it up before doing a factory reset, you have to edit the flashall script in the following way:

Windows: Open flashall.cmd in your favorite text editor, go to line #298 and change it from fastboot -w to REM fastboot -wand save the changes.

Unix: Open flashall.sh in your favorite text editor, go to line #275 and change it from $fastbootcmd -w to #$fastbootcmd -w and save the changes.

Once again, this is not encouraged as it can potentially cause issues later on. You've been warned.

Run the script

1. 1. Windows: In the CMD you opened earlier, type flashall.cmd

1. 2. Unix: In the Terminal you opened earlier, type ./flashall.sh

Note: An obvious note, do not disconnect your device from your PC while flashall script is running. Your device will reboot a few times during the execution.

Once script outputs format logdump... and the phone reboots, service firmware will be flashed.

Step 3 - Upgrade to your desired build

Enter Recovery mode via one of the following methods:

1.1. If your phone is turned on and USB debugging is enabled, use command adb reboot recovery

1.2. While in fastboot mode, navigate to Recovery Mode using Volume Up/Down buttons and select with a single press of a Power button

1.3. While in fastboot mode, issue one of the following commands : fastboot reboot recovery or fastboot oem reboot-recovery

Once in Recovery Mode, you have 2 ways to proceed:

A: Update from SD card

A.1. Select Apply update from SD card option

A.2. Navigate your SD card and select UL-ASUS_I01WD-ASUS-16.1220.1909.194-1.1.1-user.zip

A.3. Confirm your choice with a single press of the Power button

A.4. Once you're back to the menu of Recovery Mode, reboot by selecting Reboot system now and enter Recovery Mode once again via any of the above methods

A.5. Select Apply update from SD card option again

A.6. Navigate your SD card and select UL-ASUS_I01WD-ASUS-17.1810.1910.63-1.1.1-user.zip

A.7. Confirm your choice with a single press of the Power button

A.8. Once you're back to the menu of Recovery Mode, select Reboot system now

B: Update through ADB Sideload

B.1. Select Apply update from ADB option

B.2. In your CMD/ Terminal, issue command adb sideload "UL-ASUS_I01WD-ASUS-16.1220.1909.194-1.1.1-user.zip"

B.3. Once you're back to the menu of Recovery Mode, reboot by selecting Reboot system now and enter Recovery Mode once again via any of the above methods

B.4. Select Apply update from ADB again

B.5. In your CMD/ Terminal, issue command adb sideload "UL-ASUS_I01WD-ASUS-17.1810.1910.63-1.1.1-user.zip"

B.6. Once you're back to the menu of Recovery Mode, select Reboot system now

Note: Like I've mentioned earlier, these steps are specifically for build WW-17.1810.1910.63. If your target build does not require another build for an update, you can skip steps A.4 to A.7 or B3 to B5

That's pretty much it. If you followed the steps above correctly, you should once again have a running phone with your desired build of firmware.

If you have any questions, do not hesitate to ask.

Cheers.