Installing a custom ROM on Asus Zenfone Max M1 ZB555KL X00P X00PD

I own an Asus Zenfone Max M1
model ZB555KL

The codename of this phone appears to be X00PD in some places, but X00P in others. I haven’t been able to figure out whether those codes are supposed to refer to different phones.

I would like to describe how I managed to install a custom ROM on it (Lineage OS).
I didn’t figure any of this out myself but rather work entirely off the work of some amazing developers whose links are included in the various steps below.
These steps will void your warranty and they may make your phone unusuable; however in my case it works fine.

Step 1 : Set up your system

You will need a PC with adb (platform-tools) installed. You can find easily anywhere on the net how to do it.
I did this on a Linux machine.

Then you need to enter development mode in your phone, which is really easy and described here:
https://www.asus.com/support/FAQ/1009474/

To test that it works, once you connect your phone with your PC and you type in the shell:

adb devices

It should tell you it found your device.

Step 2 : Update to the latest firmware

Download the vendor firmware for Android 9 given here: https://forum.xda-developers.com/asus-zenfone-max/development/x00p-lineageos-16-0-t4047669

For your convenience this is the direct download link of the firmware zip file:
https://dlcdnets.asus.com/pub/ASUS/ZenFone/ZB555KL/UL-ASUS_X00P-WW-16.00.1906.411-user.zip

Put the firmware zip file in the root of your phone file system. I did it using USB file transfer from my PC.
Then reboot your phone. A message should appear that there is a system update or something and it will walk you through it.
I think this may wipe all data from your phone, so make a backup first!

Reference: this is the “manual” update method as described here: https://www.asus.com/support/faq/1009748

Step 3 : Unlocking the bootloader

I’m not sure if this is actually required or not. It will wipe all the data from your phone so first back it up.

I got this from the following video: https://www.youtube.com/watch?v=DyFiYL0D8Q8&feature=youtu.be
which also contains a link somewhere in the comments to a google drive zip file.

One of those files is the .apk from Asus, “UnlockTool_ASUS_Android_signed_E300_1.apk”. I think this file comes originally from Asus but I haven’t been able to find it on their site strangely enough. Not sure what’s going on there.

I installed this by connecting the phone USB cable with my PC and then typing:

adb install UnlockTool_ASUS_Android_signed_E300_1.apk

That seemed to have worked. But caution: it will basically reset the phone to “zero”.
Oh right — https://www.quora.com/What-is-the-meaning-of-an-unlocked-bootloader-in-mobile-phones

Step 4 : Installing TWRP

Then I install custom recovery, which is basically a system that allows you to make backups of your entire system and install a new operating system.

Download the file supplied here:

https://twrp.me/asus/asuszenfonemaxm1.html

Yes it says X00P (not X00PD) but it worked for my phone.

Ensure your phone is connected with USB and run this on your PC:

adb reboot bootloader

Then the phone should reboot into the bootloader. Once there you can type:

sudo fastboot flash recovery twrp-3.3.1-0-X00P.img

Or replace `twrp-3.3.1-0-X00P.img` with whatever version you downloaded.

Now switch off the phone. Caution! You need to boot *immediately* into recovery (i.e. TWRP) upon the first boot, otherwise the phone will wipe it and you have to re-do this step (as described in the link above). To boot into recovery, when the phone is powered off, press the power on button and volume down button simultaneously. Once the screen turns on, release the power button but keep pressing the volume down button until you enter the recovery environment. You should see the TWRP logo.

Then when booting into TWRP, it says it cannot decrypt data. Following something I read somewhere on a forum, I just pressed cancel to enter TWRP and it seemed to work ok.

Once you know it works, you can power off the phone again.

Step 5 : Download and install the custom ROM

Now it’s time for the fun part: installing the new system!

I followed the instructions here: https://forum.xda-developers.com/asus-zenfone-max/development/x00p-lineageos-16-0-t4047669

That is, download (1) the LineageOS Zip file and (2) GApps.

LineageOS: https://sourceforge.net/projects/teamunique/files/X00P/lineage/
Gapps: https://opengapps.org/ (ARM64 9.0 Nano Recommended)

Place both zip files on a micro SD card that you stick into your phone.

Boot into TWRP (i.e. hold down power + volume down as described above).

Press Wipe and select System, Data, Dalvik, Cache. Don’t Wipe Vendor. Press the slider to wipe.

Then go back to Install and select the two zip files that you placed on the micro SD.

That’s it, for me it worked! I hope it works for you too.