[Asus ZenFone Max Pro M1  Guides, News, & Discussio] Sudeep Duhoon:
Things needed:

1. Unlocked and Asus Zenfone Max Pro M1 (why dafaq so long name?)

2. Stock rom (recovery/fastboot doesn't matter) i used this to updated to 305, get accordingly from here

3. Modified TWRP recovery

4. Ota package

Instructions:

1. Download the full rom and ota (in your phone, from second post or get from our telegram group)

2. After download gets completed, go to /data/cache and copy dlpkgfile somewhere in sdcard, and rename it to ota.zip

3. Extract ota.zip and go to META-INF\com\google\android , open updater-script in text editor and remove these lines from it

containprop(getprop("ro.product.device")) || abort("E3004: This package is for \"ASUS_X00TD\" devices; this is a \"" + getprop("ro.product.device") + "\".");
getprop("ro.build.asus.sku") == "WW" || abort("E3009: This package is for sku: \"WW\"; this is a sku: \"" + getprop("ro.build.asus.sku") + "\".");
ui_print("Source: Android/sdm660_64/sdm660_64:8.1.0/OPM1/14.2016.1804.252-20180428:user/release-keys");
ui_print("Target: Android/sdm660_64/sdm660_64:8.1.0/OPM1/14.2016.1804.305-20180521:user/release-keys");
ui_print("Verifying current system...");
containprop(getprop("ro.build.fingerprint")) ||
abort("E3001: Package expects build fingerprint of Android/sdm660_64/sdm660_64:8.1.0/OPM1/14.2016.1804.252-20180428:user/release-keys or Android/sdm660_64/sdm660_64:8.1.0/OPM1/14.2016.1804.305-20180521:user/release-keys; this device has " + getprop("ro.build.fingerprint") + ".");

i.e. everything till

apply_patch_check("EMMC:/dev/block/bootdevice/by-name/boot:47510824:9ca7a29f3b90af90492bfa0c07275390f72f397d:47502632:80fbccb727c484733397429a9df38a499dee67fe") || abort("E3005: \"EMMC:/dev/block/bootdevice/by-name/boot:47510824:9ca7a29f3b90af90492bfa0c07275390f72f397d:47502632:80fbccb727c484733397429a9df38a499dee67fe\" has unexpected contents.");

Save it and zip back the ota

NOTE: Skip step 4 if you have stock fastboot images

4. Extract stock rom zip and go to META-INF\com\google\android , open updater-script in text editor and remove these lines from it

(!less_than_int(1524926024, getprop("ro.build.date.utc"))) || abort("E3003: Can't install this package (Sat Apr 28 22:33:44 CST 2018) over newer build (" + getprop("ro.build.date") + ").");
containprop(getprop("ro.product.device")) || abort("E3004: This package is for \"ASUS_X00TD\" devices; this is a \"" + getprop("ro.product.device") + "\".");
ui_print("Target: Android/sdm660_64/sdm660_64:8.1.0/OPM1/14.2016.1804.252-20180428:user/release-keys");
show_progress(0.650000, 0);

i.e everything till

ui_print("Patching system image unconditionally...");

Once done, zip it back

5. Reboot to bootloader and flash system.img vendor.img boot.img and modified twrp.img if you have correct version of fastboot rom, otherwise, just flash the modified twrp.img and force reboot to recovery by pressing and holding volume down + power key

6. Once in recovery, flash the rom.zip you made and right after that flash the ota.zip, once done, make a backup of boot, modem, system image, vendor image

7. (OPTIONAL) if you had decrypted data partition before, flash normal twrp using current twrp or fastboot and flash decrypt.zip again

8. (OPTIONAL) if you want rooted system no twrp and easy ota updates for future, flash magisk and stock recovery using modified twrp and reboot. you'll be able to flash ota normally after this with root access.

Enjoy.

What to do on next ota?

1. Flash the modified twrp

2. Restore the backup you made in step 6

3. Edit the ota as explained in step 3

4. Flash the ota zip and make another backup of system image, vendor image, modem, and boot (also any other partition depending on the ota)

5. Do the optional steps as said in steps 7 and 8