[GUIDE] Pixel 4a (5G) "bramble": Unlock Bootloader, Update, Root, Pass SafetyNet

[V0latyle]

Magisk Canary 23018 is out.
Changes:

• [Zygisk] Show warning in app UI to indicate incompatible Zygisk modules
• [App] Allow modules to specify an update URL for in-app update + install

Update from within Magisk to prevent problems like breaking root.

If you do not already have Magisk installed, Download it here

 

[V0latyle]

Magisk Canary updated to 23019
Changes:
- [Zygisk] Skip loading modules into the Magisk app to prevent conflicts
- [MagiskBoot] Change `zopfli` to a more reasonable config so it doesn't take forever
- [General] Several `BusyBox` changes

Preferred method of update is from within Magisk app.

If installing for the first time, here is the APK Download

 

[V0latyle]

@topjohnwu has been busy. He doesn't get nearly enough appreciation for all his hard work.

Magisk Stable is still 23.0.
Magisk Beta is now 24.0
Canary is now 24001

Magisk 24.0 discussion thread

 

[chasehammer]

Just wanted to update your question, Magisk 24001 now allows us early updaters to get root again without wipe. Tested myself and works perfectly. FINALLY! hehe.

 

[V0latyle]

Just wanted to update your question, Magisk 24001 now allows us early updaters to get root again without wipe. Tested myself and works perfectly. FINALLY! hehe.

I feel like I should explain this a little bit...

Prior to Magisk 23016, Magisk did not properly preserve parts of the boot image header when the image was patched. So, the device would see an invalid header and would fail to load the boot image.

We found a workaround where disabling verity and verification would allow the device to load the boot image anyway; the problem is, disabling verity and verification require data to be clean unless they're already disabled. This meant that running a patched boot image required disabling verity/verification, and disabling verity/verification required wiping data the first time when they had been enabled.

Magisk Canary 23016 fixed this, so when the boot image was patched the header was properly preserved, so disabling verity/verification was no longer necessary.

Also worthy of note: Temporary root has always been possible by live booting the patched image.

 

[V0latyle]

Magisk Stable is now at version 24.1, so I will no longer be providing any Magisk updates.

You can use any version of Magisk now - Stable, Beta, or Canary. as long as it is 23016 or newer.

Once again, if you want to switch versions of Maagisk, it is HIGHLY RECOMMENDED that you "Complete Uninstall" within Magisk before installing the new version. Multiple instances of Magisk can break root.

If you simply want to update Magisk, the best way to do so is from within the app.

Once the February update is out, I will perform some testing with installing to inactive slot, and if it works, I will update this guide.

Given the low activity on this thread, I will probably close it if everything goes well with the next update.

Thank you all for your testing and contributions.

 

[jackthedipper]

Hey, @V0latyle !

Have you tried installing OTA / installing magisk to inactive slot yet, does it work?

Best,
Jack

 

[V0latyle]

Hey, @V0latyle !

Have you tried installing OTA / installing magisk to inactive slot yet, does it work?

Best,
Jack

I personally have not, however other people have and it works for most of them

 

[yekrut]

Magisk Stable is now at version 24.1, so I will no longer be providing any Magisk updates.

You can use any version of Magisk now - Stable, Beta, or Canary. as long as it is 23016 or newer.

Once again, if you want to switch versions of Maagisk, it is HIGHLY RECOMMENDED that you "Complete Uninstall" within Magisk before installing the new version. Multiple instances of Magisk can break root.

If you simply want to update Magisk, the best way to do so is from within the app.

I did the OTA update to A12+March update and lost root so Magisk can no longer do a complete uninstall. But I really need to reroot because I live in a country where I can't use the local networks without Magisk mods to unlock the networks. (China) What is the safest way to get back to a working Magisk root?

I'm pretty new to all of this. I bought the phone already rooted from an internet seller. I've been reading threads on this forum for 5 or 6 hours but frankly the guides and methods have been in discussion for the last year or more and I have no idea what's still current.

I *think* I need to unlock the bootloader.
I *think* I need to update the radio and something else I can't find now.
I think I need to do a factory reset, or reset to stock, and data wipe.
I think I need to do all that before I can start the root process again but I'm worried I'll overlook something and destroy my phone.

The problem is that everything uses the phone in China. I use it to pay for everything, I use it for the 'green code' to enter businesses. Without it I have nothing.

 

[V0latyle]

I did the OTA update to A12+March update and lost root so Magisk can no longer do a complete uninstall. But I really need to reroot because I live in a country where I can't use the local networks without Magisk mods to unlock the networks. (China) What is the safest way to get back to a working Magisk root?

I'm pretty new to all of this. I bought the phone already rooted from an internet seller. I've been reading threads on this forum for 5 or 6 hours but frankly the guides and methods have been in discussion for the last year or more and I have no idea what's still current.

I *think* I need to unlock the bootloader.
I *think* I need to update the radio and something else I can't find now.
I think I need to do a factory reset, or reset to stock, and data wipe.
I think I need to do all that before I can start the root process again but I'm worried I'll overlook something and destroy my phone.

The problem is that everything uses the phone in China. I use it to pay for everything, I use it for the 'green code' to enter businesses. Without it I have nothing.

Everything in the OP is current, with the exception of the deprecated spoiler. It's actually very hard to destroy your device unless you do something deliberately wrong.

Green code? Is that the health code app they're talking about that's a thinly veiled means of social control? This is why we Americans have been so resistant to such measures - freedom is sacred to us.

 

[yekrut]

Everything in the OP is current, with the exception of the deprecated spoiler. It's actually very hard to destroy your device unless you do something deliberately wrong.

Green code? Is that the health code app they're talking about that's a thinly veiled means of social control? This is why we Americans have been so resistant to such measures - freedom is sacred to us.

In fact I'm American. I teach English in China at the moment. And yes, they use apps for contact tracing. There's a health code that monitors if you've been near a person later identified as having coronavirus. Then there is a travel code used to show if you've been to an area with elevated risk, and each city/province has its own way of checking into an address via app. The local app is so screwed up that it set my nationality to the UAE instead of USA and I can't change it.

I need my phone for everything. Stores won't allow you to enter without being able to generate a code, which I can't do without phone signal. I can't take a bus, or communicate via translation, or take a taxi without it.

So after knowing about my phone situation, which of those guides do you recommend I follow? It seems that I need to remove any old traces of Magisk as well as do a factory reset, but I can't uninstall in Magisk. I've read a lot of your posts from the last year and I know you know this subject well. A few more days without a phone isn't an option. What would you do?

 

[V0latyle]

In fact I'm American. I teach English in China at the moment. And yes, they use apps for contact tracing. There's a health code that monitors if you've been near a person later identified as having coronavirus. Then there is a travel code used to show if you've been to an area with elevated risk, and each city/province has its own way of checking into an address via app. The local app is so screwed up that it set my nationality to the UAE instead of USA and I can't change it.

I need my phone for everything. Stores won't allow you to enter without being able to generate a code, which I can't do without phone signal. I can't take a bus, or communicate via translation, or take a taxi without it.

That's actually kinda terrifying. Imagine your whole life depending on something the government is using to track you. Apparently that app is known for transmitting private data to the PRC MSS...

After I had Covid, the county called me (apparently the hospital gave them my contact information) to try to conduct contact tracing. I told them in no uncertain terms that it was a breach of my privacy, so they could take a long walk off a short pier.

So after knowing about my phone situation, which of those guides do you recommend I follow? It seems that I need to remove any old traces of Magisk as well as do a factory reset, but I can't uninstall in Magisk. I've read a lot of your posts from the last year and I know you know this subject well. A few more days without a phone isn't an option. What would you do?

I have no idea what methods that app uses to detect root or Magisk. If you want to retain root, you could try the Universal SafetyNet Fix module, and configure DenyList on the contact tracing app.

If you need to return your device to complete stock, you can use the Android Flash Tool to return your device to factory stock. Your bootloader must be unlocked to do this, but in the tool options you can specify to relock your bootloader. In this case, I would check the Wipe Device, Force flash all partitions and Lock bootloader options.

 

[yekrut]

I have no idea what methods that app uses to detect root or Magisk. If you want to retain root, you could try the Universal SafetyNet Fix module, and configure DenyList on the contact tracing app.

If you need to return your device to complete stock, you can use the Android Flash Tool to return your device to factory stock. Your bootloader must be unlocked to do this, but in the tool options you can specify to relock your bootloader. In this case, I would check the Wipe Device, Force flash all partitions and Lock bootloader options.

My root is gone after A12 OTA update. It still has magisk, but no super user ability or modules. It's just an empty shell showing the Magisk version. If I had realized updating would cause all these issues I wouldn't have done it. I didn't know the automatic update would do so much damage (and I really hate the new UI).

edit: Bootloader has to be unlocked to re-root after reverting to stock, right?

 

[V0latyle]

My root is gone after A12 OTA update. It still has magisk, but no super user ability or modules. It's just an empty shell showing the Magisk version. If I had realized updating would cause all these issues I wouldn't have done it. I didn't know the automatic update would do so much damage (and I really hate the new UI).

The A11 images are still available, and you can downgrade your device if you so desire.

edit: Bootloader has to be unlocked to re-root after reverting to stock, right?

I thought I made this clear. The only thing you can do on a locked bootloader is sideload the OTA. To flash partitions, such as with the Android Flash Tool, your bootloader must be unlocked. If you choose to return to bone stock and don't wish to root, you can re lock it, and the Android Flash Tool provides for this.

 

[yekrut]

The A11 images are still available, and you can downgrade your device if you so desire.

I thought I made this clear. The only thing you can do on a locked bootloader is sideload the OTA. To flash partitions, such as with the Android Flash Tool, your bootloader must be unlocked. If you choose to return to bone stock and don't wish to root, you can re lock it, and the Android Flash Tool provides for this.

Thanks, that is clear. Unfortunately I need to root in order to use mainland China cell towers, hence my predicament. So I plan to make sure the bootloader is still unlocked, then use the Android Flash Tool to put everything back to bone stock, then reinstall Magisk to root. Thank you

 

[V0latyle]

Thanks, that is clear. Unfortunately I need to root in order to use mainland China cell towers, hence my predicament. So I plan to make sure the bootloader is still unlocked, then use the Android Flash Tool to put everything back to bone stock, then reinstall Magisk to root. Thank you

Make damn sure you use a VPN, and encrypt your device.

 

[yekrut]

Can I let Android Flash Tool lock the bootloader AFTER I have returned to stock and rooted with Magisk on it? In effect, to be able to turn on the phone without pressing the power button twice first? I've seen that the device must be wiped in order to unlock the bootloader but how about relock?

 

[V0latyle]

Can I let Android Flash Tool lock the bootloader AFTER I have returned to stock and rooted with Magisk on it? In effect, to be able to turn on the phone without pressing the power button twice first? I've seen that the device must be wiped in order to unlock the bootloader but how about relock?

The Android Flash Tool will not perform individual actions. You cannot simply choose one action without flashing a complete firmware set, such as flashing a single partition, wiping the device, or locking the bootloader.
You can, however, perform this manually through the ADB/fastboot terminal.

As for the unlocked bootloader warning, you don't have to take any action when it displays. Simply ignore it, the device continues in about 5 seconds.

Do not lock the bootloader on modified firmware. Locking the bootloader enables Android Verified Boot, wherein the device checks the boot image against a reference hash while it's loading. Any modification to the boot image, such as a Magisk patch, will fail verification, preventing boot. It is possible in some cases to lock the bootloader on a custom ROM, when a custom root of trust has been set; however, I am not aware of any available ROMs for the Pixel series that accommodate this.

Therefore, if you're going to lock the bootloader, ensure the device is returned to bone stock before doing so.

 

[yekrut]

The Android Flash Tool will not perform individual actions. You cannot simply choose one action without flashing a complete firmware set, such as flashing a single partition, wiping the device, or locking the bootloader.
You can, however, perform this manually through the ADB/fastboot terminal.

As for the unlocked bootloader warning, you don't have to take any action when it displays. Simply ignore it, the device continues in about 5 seconds.

Do not lock the bootloader on modified firmware. Locking the bootloader enables Android Verified Boot, wherein the device checks the boot image against a reference hash while it's loading. Any modification to the boot image, such as a Magisk patch, will fail verification, preventing boot. It is possible in some cases to lock the bootloader on a custom ROM, when a custom root of trust has been set; however, I am not aware of any available ROMs for the Pixel series that accommodate this.

Therefore, if you're going to lock the bootloader, ensure the device is returned to bone stock before doing so.

Thanks, that is good info. I had decided not to try to lock it again since doing everything useful except OTA updates seems to require it to be unlocked. Now I understand more about how that works.

I still have one question before I'm ready to take the plunge and try to go through these steps. I have seen places in your guides where you say that the radio img and boot image need to be newer than the installed version, otherwise the update will fail. How can a phone go from version 12 to 11 without failing that criterion? Is it because in one case an update is being performed and in the other case a fresh, "initial" OS is being installed?

 

[V0latyle]

Thanks, that is good info. I had decided not to try to lock it again since doing everything useful except OTA updates seems to require it to be unlocked. Now I understand more about how that works.

I still have one question before I'm ready to take the plunge and try to go through these steps. I have seen places in your guides where you say that the radio img and boot image need to be newer than the installed version, otherwise the update will fail. How can a phone go from version 12 to 11 without failing that criterion? Is it because in one case an update is being performed and in the other case a fresh, "initial" OS is being installed?

The androidinfo script in the factory image checks the bootloader and radio versions before applying the update. If they are not equal to, or newer than, the bootloader and radio versions contained in the factory zip, the update will fail.

However, if you choose to downgrade, this is largely irrelevant. If you downgrade via Android Flash Tool, it will flash the bootloader and radio images that came with the release you're installing. On the other hand, if you manually flash the factory image via the command line, I believe you can install an older version of Android on a newer bootloader/radio combo.