[Google Pixel 4 XL Guides, News, & Discussion] i5lee8bit:
IMPORTANT!! THESE FILES / THIS THREAD IS FOR PIXEL 4 XL "CORAL" ONLY, NOT PIXEL 4 "FLAME"!!

**IT IS HIGHLY RECOMMENDED TO PATCH THE STOCK BOOT IMAGE YOURSELF, FROM YOUR OWN DEVICE, USING MAGISK MANAGER. WHILE THERE'S A GOOD CHANCE THE FILE I PROVIDED BELOW WILL BE IDENTICAL (USE A FILE HASH CHECKSUM TOOL IF YOU'RE CURIOUS), THERE IS ALSO A CHANCE THEY MAY HAVE SMALL, BUT SIGNIFICANT, VARIANCES**

Thanks for the info and link, @wrongway213

Link to @topjohnwu's post: twitter dot com /topjohnwu/status/1272136975022084097?s=19 (until I figure out how to stop new XDA from forcing the URL to embed a giant twitter posting in the middle of the post...)

ALL FILES BELOW ARE FOR "RQ1A.210205.004, Feb 2021"!

Magisk v21.4 Patched Boot Image: https://www.androidfilehost.com/?fid=17248734326145727319

Factory Untouched Boot Image: https://www.androidfilehost.com/?fid=17248734326145727317

Factory Untouched DTBO Image: https://www.androidfilehost.com/?fid=17248734326145727318

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-------------UPDATE PROCESS BELOW-------------

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EASY UPDATE / SEAMLESS KEEP-ROOT UPDATE PROCESS

(using a PC - a very intuitive, effective, and relatively safe method).

** You can only follow this guide verbatim if coming

EXACTLY from build "11.0.0 (RQ1A.210105.003, Jan 2021)"

. But the general idea is the same for other builds, you just need the correct files for your device.

coral-rq1a.210105.003-factory-dtbo.img: https://www.androidfilehost.com/?fid=17248734326145709335

coral-rq1a.210105.003-factory-boot.img: https://www.androidfilehost.com/?fid=17248734326145709334

February 2021 sideload OTA zip: https://dl.google.com/dl/android/aosp/coral-ota-rq1a.210205.004-8fe8685c.zip

DO NOT BOOT BACK INTO O/S UNTIL ALL STEPS ARE COMPLETED - THIS ENSURES EVERYTHING BOOTS BACK UP WITH MAGISK / EDXPOSED ALL RUNNING PROPERLY RIGHT AWAY

1. boot into bootloader

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** I was on custom kernel, so I needed to flash BOTH the stock boot and dtbo images

2. fastboot flash boot coral-rq1a.210105.003-factory-boot.img

3. fastboot flash dtbo coral-rq1a.210105.003-factory-dtbo.img

......* these steps to restore stock recovery; dtbo.img also necessary for some kernel installations.

......* won't hurt to flash both anyway, so if you're unsure, go ahead and do both.

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4. use volume keys to change selection to boot to Recovery Mode

......- when you reach the android symbol with No Command, hold power button, tap volume up, in case you've forgotten

5. choose option "Apply update from ADB"

6. adb sideload coral-ota-rq1a.210205.004-8fe8685c.zip

7. Once the OTA sideload is done, Reboot to bootloader (you'll also notice it's now on the other slot after OTA flashed)

8. fastboot flash boot coral-rq1a.210205.004-magisk_patched-21.4.img

9. done, start the phone

(Optional - Flash custom kernel. If you had a custom kernel, you need to re-flash it)

This is a 100% seamless update that requires no additional / re-setup of any of my Magisk or EdXposed setups. All of the factory files can be found here https://developers.google.com/android/images. boot.img and dtbo.img are in their corresponding full Factory Image zips, and the ota zip is under Full OTA Images.

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-------------------TROUBLESHOOTING-------------------

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Issues after updating?

If you end up unable to boot or bootlooping afterwards, you most likely have an old Magisk module that isn't playing nice with the new build. There are 2 main things you can do:

1. Flash the new factory untouched boot image. You will of course lose root, and all modules will be disabled. However, it should at least get you able to boot back up quickly and have a working phone if you're in a bind.

2. I would recommend checking Tulsadiver's thread: https://xdaforums.com/pixel-4-xl/how-to/magisk-modules-disabler-booting-magisk-t3990557

Instead of reverting to stock boot image, fastboot boot (NOT FLASH) Tulsadiver's boot image. This will boot your phone in Magisk Core-Only Mode, with all modules disabled but root retained. From here you can open Magisk Manager and disable suspect modules. Before rebooting, go to Magisk Manager's settings and disable Magisk Core-Only Mode. Once you disable the incompatible module, the phone should boot back up.

- See this post (or thread) for more tips / context / an example: https://xdaforums.com/showpost.php?p=82509691&postcount=16

** As of newer Magisk builds, you can just try booting up in safe mode, which should disable Magisk and allow you to disable whatever needs to be disabled. Haven't needed to try it yet, so I can't go into more detail, but I would recommend trying that instead.