How to disable dm-verity or Android Verified Boot (AVB)

[Tutorial] How to disable dm-verity or Android Verified Boot (AVB)

hovatek
Administrator

49,778

17-03-2020, 10:29 PM

#1

This is a quick guide showing how to disable dm-verity or Android Verified Boot (AVB). Disabling dm-verity / AVB is only important if you intend to flash custom images such as patched boot, custom recoveries or even custom roms onto your device. Skipping this will result in a Red State warning and boot loop

See the video below or @ https://youtu.be/Oa6ZCb-61B0

Method 1 - Manually patching boot.img using hex editor

Requirements

Ideal for devices with Android Verified Boot 1.0 (commonly found in Android 8)
Stock boot.img for your phone model (it's best it's for your Build Number / Variant ). You can extract from the stock ROM / firmware of your device (you may check our firmware collection) OR backup from your device using any method at the forum e.g Wwr_Mtk, Miracle Box, CM2, Nck Box Pro etc
Hxd hex editor ; download @ https://mh-nexus.de/en/hxd/
Install adb and fastboot

Follow the steps below to patch boot.img manually to remove/disable dm-verity

Launch Hxd hex editor tool
Drag and drop your boot.img onto HxD hex editor window
Click Search > Replace
In the Replace windows, Click the Hex-values tab and input the following below

Search for 2C 76 65 72 69 66 79
replace with 00 00 00 00 00 00 00
Click "Replace all"
You can confirm if all traces of "verify" have been removed, by clicking Search > find > Text-string

Search for verify
Click Search all, and you should get a prompt "Can't find verify", click OK
Click File > save
The original unmodified file will be saved as boot.img.bak while the new modified file will be saved as boot.img
You can now flash the newly patched boot.img using fastboot to remove dm-verity from your device

Code:

adb devices adb reboot-bootloader fastboot devices fastboot flash boot boot.img

Method 2 - Patching boot.img using Magisk Manager

Requirements

Ideal for devices with Android Verified Boot 1.0 (commonly found in Android 8)
Stock boot.img for your phone model (it's best it's for your Build Number / Variant ). You can extract from the stock ROM / firmware of your device (you may check our firmware collection) OR backup from your device using any method at the forum e.g Wwr_Mtk, Miracle Box, CM2, Nck Box Pro etc
Download Latest Magisk Manager apk @ https://github.com/topjohnwu/Magisk/releases
Active internet connection on your Android device
Install adb and fastboot

Follow the steps below to patch boot.img using Magisk Manager to remove dm-verity

Copy the stock boot.img of your device to your phone's internal storage or SD card
On your phone, launch the Magisk Manager app
If you're not using the latest version, you'll have to update the app first before proceeding
Click "Advanced settings" > Untick the checkbox beside "Preserve AVB 2.0/dm-verity"
Select Install > Install > Patch Boot Image File >
Navigate to the location of the stock boot.img you copied earlier on, then Select it.
Note that if you are using a Samsung device then you should select the AP of your device's firmware in .tar format instead of boot.img
Magisk Manager should begin downloading the magisk zip file used for patching
Once the download is complete, Magisk Manager will automatically patch the file and store it under SDcard/Download/magisk_patched.img[.tar]
You can now flash the magisk_patched boot using fastboot or AP using Odin to remove dm-verity from your device

Code:

adb devices adb reboot-bootloader fastboot devices fastboot flash boot magisk_patched.img

Method 3 - Flashing blank vbmeta

Requirements

Ideal for devices with Android Verified Boot 2.0 (commonly found in Android 9 and above)
Device with /vbmeta partition
Download empty vbmeta.img @ [ Login to download] if your device doesn't require a signed vbmeta or generate a custom signed vbmeta if it does
Install adb and fastboot

Follow the steps below to flash vbmeta.img to remove dm-verity

Copy the vbmeta.img into your adb and fastboot folder
You can now flash the vbmeta.img using fastboot to remove dm-verity from your device

Code:

adb devices adb reboot-bootloader fastboot devices fastboot flash vbmeta vbmeta.img

Method 4 - Flashing stock vbmeta with flags

This method is ideal for cases where the blank vbmeta method doesn't work or you wish to remove WARNING: LOCK FLAG IS: UNLOCK, SKIP VERIFY!!! message during boot

Requirements

Ideal for devices with Android Verified Boot 2.0 (commonly found in Android 9 and above)
Userdata encryption should be disabled else the --disable-verification flag will result in a boot loop
Stock vbmeta.img

Follow the steps below to flash vbmeta.img to remove dm-verity

Copy the vbmeta.img into your adb and fastboot folder
You can now flash the vbmeta.img using fastboot to remove dm-verity from your device

Code:

adb devices adb reboot-bootloader fastboot devices fastboot oem cdms fastboot --disable-verity --disable-verification flash vbmeta vbmeta.img

Important Notice

If your device gets stuck in a white screen with "Sysdumpping now, keep power on" text then flash back stock vbmeta
If your device runs on Android 9 and above (or AVB 2.0), then you must use method 3 or 4 as other methods won't work for your device
If your device runs on Android 8.x (Oreo), then you can try either method 1 or 2
If Magisk-patched boot (which also includes root) boot loops your device then you can try method 1 instead then use a custom recovery to attempt flashing SuperSU (no longer maintained) zip to get root
If you've tried method 1 and nothing has been replaced then you should use method 2 and let magisk do the patching
Some models don't play nice with a blank or custom vbmeta. For such models, you use method 4

This post was last modified: 10-03-2024, 07:11 AM by hovatek.

ikasemota
Junior Member

36

29-04-2020, 02:21 PM

#2

Do I need to unlock the bootloader before I could proceed on method #3?

This post was last modified: 29-04-2020, 02:24 PM by ikasemota.

hovatek
Administrator

49,778

30-04-2020, 01:00 AM

#3

(29-04-2020, 02:21 PM)ikasemota Do I need to unlock the bootloader before I could proceed on method #3?

yes

Mitchie Boom
Enthusiastic Member

10

07-05-2020, 05:43 PM

#4

Hi I successfully ported a TWRP from my stock recovery however when I'm going to flash an image there was no system partitions and other partitions, what should I do?

hovatek
Administrator

49,778

08-05-2020, 12:00 PM

#5

(07-05-2020, 05:43 PM)Mitchie Boom Hi I successfully ported a TWRP from my stock recovery however when I'm going to flash an image there was no system partitions and other partitions, what should I do?

already replied to @ https://www.hovatek.com/forum/thread-218...#pid192649

This post was last modified: 08-05-2020, 12:07 PM by X3non.

desexiet
Experienced Member

96

11-05-2020, 01:33 AM

#6

(07-05-2020, 05:43 PM)Mitchie Boom Hi I successfully ported a TWRP from my stock recovery however when I'm going to flash an image there was no system partitions and other partitions, what should I do?

Were you able to install the ported TWRP successfully?

mainframe
Newbie

2

30-05-2020, 12:28 PM

#7

Hi,

I was following your instructions of creating a custom vbmeta with all the keys (boot key modified) and this guide to flash a patched boot
img, but i am stuck on flashing anything with fastboot. No matter if it is original or patched, it is always stuck like this:

Rewriting vbmeta struct at offset: 0
Sending 'vbmeta' (1024 KB) OKAY [ 0.043s]
Writing 'vbmeta'

I would appreciate any thoughts on my conundrum.

/edit: The bootloader is unlocked (also by following a hovatek guide with the modified fastboot)

This post was last modified: 30-05-2020, 01:02 PM by mainframe.

hovatek
Administrator

49,778

30-05-2020, 10:48 PM

#8

(30-05-2020, 12:28 PM)mainframe Hi,

I was following your instructions of creating a custom vbmeta with all the keys (boot key modified) and this guide to flash a patched boot
img, but i am stuck on flashing anything with fastboot. No matter if it is original or patched, it is always stuck like this:

Rewriting vbmeta struct at offset: 0
Sending 'vbmeta' (1024 KB) OKAY [ 0.043s]
Writing 'vbmeta'

I would appreciate any thoughts on my conundrum.

/edit: The bootloader is unlocked (also by following a hovatek guide with the modified fastboot)

did you try using the fastboot binary used while unlocking bootloader?
if you still have problems then create a new thread for this issue..click the "ask question" button at the top

ikasemota
Junior Member

36

24-06-2020, 10:38 AM

#9

Please I read somewhere that it is also possible to flash an image file with SP flash tool without unlocking the bootloader. How true is that?

hovatek
Administrator

49,778

25-06-2020, 10:16 AM

#10

(24-06-2020, 10:38 AM)ikasemota Please I read somewhere that it is also possible to flash an image file with SP flash tool without unlocking the bootloader. How true is that?

true (if the device in question allows flashing custom images ie non-verified or -sign images using spft) but you should also note that on recent android versions the chances are you'll brick the phone if you flash custom images without unlocking bootloader as a locked bootloader will always attempt to verify the integrity of OS before booting

This post was last modified: 25-06-2020, 10:18 AM by X3non.

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Method 1 - Manually patching boot.img using hex editor

Requirements

Method 2 - Patching boot.img using Magisk Manager

Requirements

Method 3 - Flashing blank vbmeta

Requirements

Method 4 - Flashing stock vbmeta with flags

Requirements

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