[GUIDE] Pixel 4 "flame": Unlock Bootloader, Update, Root, Pass SafetyNet

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V0latyle

Forum Moderator
Staff member
If you are looking for my guide on a different Pixel, find it here:
WARNING: YOU AND YOU ALONE ARE RESPONSIBLE FOR ANYTHING THAT HAPPENS TO YOUR DEVICE. THIS GUIDE IS WRITTEN WITH THE EXPRESS ASSUMPTION THAT YOU ARE FAMILIAR WITH ADB, MAGISK, ANDROID, AND ROOT. IT IS YOUR RESPONSIBILITY TO ENSURE YOU KNOW WHAT YOU ARE DOING.

Prerequisites:


Android Source - Setting up a device for development


  1. Follow these instructions to enable Developer Options and USB Debugging.
  2. Enable OEM Unlocking. If this option is grayed out, unlocking the bootloader is not possible.
  3. Connect your device to your PC, and open a command window in your Platform Tools folder.
  4. Ensure ADB sees your device:
    Code:
    adb devices
    If you don't see a device, make sure USB Debugging is enabled, reconnect the USB cable, or try a different USB cable.
    If you see "unauthorized", you need to authorize the connection on your device.
    If you see the device without "unauthorized", you're good to go.
  5. Reboot to bootloader:
    Code:
    adb reboot bootloader
  6. Unlock bootloader: THIS WILL WIPE YOUR DEVICE!
    Code:
    fastboot flashing unlock
    Select Continue on the device screen.

  1. Install Magisk on your device.
  2. Download the factory zip for your build.
  3. Inside the factory zip is the update zip: "device-image-buildnumber.zip". Open this, and extract boot.img
  4. Copy boot.img to your device.
  5. Patch boot.img with Magisk: "Install" > "Select and Patch a File"
  6. Copy the patched image back to your PC. It will be named "magisk_patched-23xxx_xxxxx.img". Rename this to "master root.img" and retain it for future updates.
  7. Reboot your device to bootloader.
  8. Flash the patched image:
    Code:
    fastboot flash boot <drag and drop master root.img here>
  9. Reboot to Android. Open Magisk to confirm root - under Magisk at the top, you should see "Installed: <Magisk build number>

  1. Before you download the OTA, open Magisk, tap Uninstall, then Restore Images. If you have any Magisk modules that modify system, uninstall them now.
  2. Take the OTA update when prompted. To check for updates manually, go to Settings > System > System Update > Check for Update
  3. Allow the update to download and install. DO NOT REBOOT WHEN PROMPTED. Open Magisk, tap Install at the top, then Install to inactive slot. Magisk will then reboot your device.
  4. You should now be updated with root.

  1. Download the OTA.
  2. Reboot to recovery and sideload the OTA:
    Code:
    adb reboot sideload
    Once in recovery:
    Code:
    adb sideload ota.zip
  3. When the OTA completes, you will be in recovery mode. Select "Reboot to system now".
  4. Allow system to boot and wait for the update to complete. You must let the system do this before proceeding.
  5. Reboot to bootloader.
  6. Boot the master root image (See note 1):
    Code:
    fastboot boot <drag and drop master root.img here>
    Note: If you prefer, you can download the factory zip and manually patch the new boot image, then flash it after the update. Do not flash an older boot image after updating.
  7. Your device should boot with root. Open Magisk, tap Install, and select Direct Install.
  8. Reboot your device. You should now be updated with root.
Note: You can use Payload Dumper to extract the contents of the OTA if you want to manually patch the new boot image. However, I will not cover that in this guide.

Please note that the factory update process expects an updated bootloader and radio. If these are not up to date, the update will fail.
  1. Download the factory zip and extract the contents.
  2. Reboot to bootloader.
  3. Compare bootloader versions between phone screen and bootloader.img build number
    Code:
    fastboot flash bootloader <drag and drop new bootloader.img here>
    If bootloader is updated, reboot to bootloader.
  4. Compare baseband versions between phone screen and radio.img build number
    Code:
    fastboot flash radio <drag and drop radio.img here>
    If radio is updated, reboot to bootloader.
  5. Apply update:
    Code:
    fastboot update --skip-reboot image-codename-buildnumber.zip
    When the update completes, the device will be in fastbootd. Reboot to bootloader.
  6. Boot the master root image (See note 1):
    Code:
    fastboot boot <drag and drop master root.img here>
    Note: If you prefer, you can manually patch the new boot image, then flash it after the update. Do not flash an older boot image after updating.
  7. Your device should boot with root. Open Magisk, tap Install, and select Direct Install.
  8. Reboot your device. You should now be updated with root.
Note: If you prefer, you can update using the flash-all script included in the factory zip. You will have to copy the script, bootloader image, radio image, and update zip into the Platform Tools folder; you will then have to edit the script to remove the -w option so it doesn't wipe your device.
The scripted commands should look like this:
Code:
fastboot flash bootloader <bootloader image name>
fastboot reboot bootloader
ping -n 5 127.0.0.1 > nul
fastboot flash radio <radio image name>
fastboot reboot bootloader
ping -n 5 127.0.0.1 > nul
fastboot update  --skip-reboot --slot=all <image-device-buildnumber.zip>
Once this completes, you can reboot to bootloader and either boot your master patched image, or if you patched the new image, flash it at this time.

  1. Follow the instructions on the Android Flash Tool to update your device. Make sure Lock Bootloader and Wipe Device are UNCHECKED.
  2. When the update completes, the device will be in fastbootd. Reboot to bootloader.
  3. Boot the master root image (See note 1):
    Code:
    fastboot boot <drag and drop master root.img here>
    Note: If you prefer, you can download the factory zip and manually patch the new boot image, then flash it after the update. Do not flash an older boot image after updating.
  4. Your device should boot with root. Open Magisk, tap Install, and select Direct Install.
  5. Reboot your device. You should now be updated with root.

This is my configuration that is passing Safety Net. I will not provide instructions on how to accomplish this. Attempt at your own risk.

Zygisk + DenyList enabled
All subcomponents of these apps hidden under DenyList:
  • Google Play Store
  • GPay
  • Any banking/financial apps
  • Any DRM media apps
Modules:
To check SafetyNet status:
I do not provide support for Magisk or modules. If you need help with Magisk, here is the Magisk General Support thread. For support specifically with Magisk v24+, see this thread.

Points of note:
  • The boot image is NOT the bootloader image. Do not confuse the two - YOU are expected to know the difference. Flashing the wrong image to bootloader could brick your device.
  • While the Magisk app is used for patching the boot image, the app and the patch are separate. This is what you should see in Magisk for functioning root:
    screenshot_20211218-194517-png.5486339
  • "Installed" shows the version of patch in the boot image. If this says N/A, you do not have root access - the boot image is not patched, or you have a problem with Magisk.
  • "App" simply shows the version of the app itself.
  • If you do not have a patched master boot image, you will need to download the factory zip if you haven't already, extract the system update inside it, then patch boot.img.
  • If you prefer updating with the factory image, you can also extract and manually patch the boot image if desired.
  • Some Magisk modules, especially those that modify read only partitions like /system, may cause a boot loop after updating. As a general rule, disable these modules before updating. You are responsible for knowing what you have installed, and what modules to disable.


Credits:
Thanks to @ipdev , @kdrag0n , @Didgeridoohan , and last but not least, @topjohnwu for all their hard work!
 
Last edited:

largeruk

Senior Member
Aug 4, 2011
100
6
@V0latyle The Pixel phone I'm rooting belongs to a friend who wants it rooted. Prior to doing anything (thankfully!), I established that the phone is actually a Pixel 4, not a 4a.

I downloaded the correct stock image for that model and then followed all your instructions. This included updating the bootloader and radio from the factory stock zip before flashing the Magisk-patched boot image.

Everything went well and the phone is now rooted with your recommended Magisk modules to pass SafetyNet. However, the wifi no longer works on the phone. I don't have his sim to test if mobile signal/data works. Thinking the problem might be the new radio, I found and reflashed the oId radio image but no joy.

What steps do I need to take to resolve the situation and get wifi working again?

Thanks for your help.

UPDATE: I've managed to restore the phone back to stock firmware (Mar 22 flame for Pixel 4 - the version it was given to me in) ang got the wifi working again. The bootloader is still unlocked. I cannot figure out what I did in the rooting process that affected the functioning of the wifi :unsure:
 
Last edited:

V0latyle

Forum Moderator
Staff member
@V0latyle The Pixel phone I'm rooting belongs to a friend who wants it rooted. Prior to doing anything (thankfully!), I established that the phone is actually a Pixel 4, not a 4a.

I downloaded the correct stock image for that model and then followed all your instructions. This included updating the bootloader and radio from the factory stock zip before flashing the Magisk-patched boot image.

Everything went well and the phone is now rooted with your recommended Magisk modules to pass SafetyNet. However, the wifi no longer works on the phone. I don't have his sim to test if mobile signal/data works. Thinking the problem might be the new radio, I found and reflashed the oId radio image but no joy.

What steps do I need to take to resolve the situation and get wifi working again?

Thanks for your help.

UPDATE: I've managed to restore the phone back to stock firmware (Mar 22 flame for Pixel 4 - the version it was given to me in) ang got the wifi working again. The bootloader is still unlocked. I cannot figure out what I did in the rooting process that affected the functioning of the wifi :unsure:
I had your post moved to this thread to keep the other one on topic.

I don't think there's anything you could have possibly done during the flashing or patching process to cause WiFi to stop working. Try again using the latest update; make absolutely sure it's for "flame", no other version.