Black screen after booting Android 9 beta (ZC520KL)

[andrewfehr]

Please tell us some basic information before asking for help:
Model Name: ZC520KL
Firmware Version: WW-AOSP-16.0200.1907.18
Rooted or not: No
Frequency of Occurrence: Every boot up
APP Name & APP Version (If your issue relates to the app): N/A
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I have been trying to install the android 9 beta on my zenfone but I keep running into the same issue. Every time I try to boot up, I'm able to make it up to the Zenfone boot animation but then the screen just turns black and android does not start up. Occasionally, the screen shows the just a sec screen and the loading icon but that quickly turns to black. I am willing to provide more information but I do not know what would be helpful so any assistance and suggestions would be greatly appreciated.

[Christine_ASUS]

Hi andrewfehr
Thank you for asking. Please check if your previous firmware version is the latest Android 8 version (WW-15.2016.1907.519) before the Android 9 AOSP release.
#ZC520KL Firmware Spot
https://www.asus.com/Phone/ZenFone-4-Max-ZC520KL/HelpDesk_BIOS/

Please try to upgrade with SD card via PC download from ASUS offical site again.
#SD card manual update guide
https://www.asus.com/support/FAQ/1039929
1. First, try to install "WW-AOSP-16.0200.1907.18"
2. If it doesn't work, try to install "ZC520KL_P_downgrade_to_O" then try to install "WW-AOSP-16.0200.1907.18"

[andrewfehr]

I tried your suggestions but I still get the same problem.

[Christine_ASUS]

Hi andrewfehr
Could you enter to "recovery mode"? Please try following steps to access recovery mode.
1. Keep pressing "volume down key"
2. Press "power key" and stop press " power key" once you feel the vibration
3. Still keep pressing "volume down key" and stop press "volume down key" once you enter [Android Recovery] Screen
4. Choose "Wipe data/factory reset"
#Hardware Reset Guide
https://www.asus.com/support/FAQ/1006346/

If the situation remain the same, could you provide me a video about how you upgrade your phone with SD card? Have you completed the upgrade yet could not boot up the phone properly?

[andrewfehr]

Everytime I've tried to install the beta i've been installing it from recovery mode. When I wipe the data and then reboot, I get to the just a sec screen and after a couple seconds, that turns to black. I have attached a dmesg log if that is of any assistance to you.