How To Guide [Magisk][US/CAN BL Unlock] Root for Galaxy S21 Series (B/N/0/U/U1/W)

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Simba2022

New member
Feb 16, 2022
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Once the phone is on Android 12 is there a way to rollback to Android 11? I'm trying in Odin and its not working.
 
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Simba2022

New member
Feb 16, 2022
4
0
Oh sorry its a SM-G991B TPA Country code, Baseband is G981BXXU5BTJ7. I've already unlocked the bootloader too. Just tried flashing a stock Android 11 firmware with Odin and it wasn't seeming to work. Phone was already on Android 12 when i got it latest firmware.
 
afaneh92

afaneh92

Senior Member
Jul 31, 2012
3,665
5,098
Simba2022 said:
Oh sorry its a SM-G991B TPA Country code, Baseband is G981BXXU5BTJ7. I've already unlocked the bootloader too. Just tried flashing a stock Android 11 firmware with Odin and it wasn't seeming to work. Phone was already on Android 12 when i got it latest firmware.
Click to expand...
Click to collapse
you are on v5 and android 11 is v3 bootloader no way
 
Ivymike52

Ivymike52

Senior Member
May 10, 2010
276
25
Marrara
As i told, i patched AP from DEVB1 firmware with magisk, as usual.
When i lanch flashing with magisk, at UH and VBMETA process stops.

I have to unplug cable and reboot phone
 
sketchscarz

sketchscarz

Senior Member
Mar 2, 2011
229
95
Eugene
Verizon Samsung Galaxy S7
ZTE Blade V9
so weird thing i noticed.. I have and eSIM as a second SIM card but not dual sim slots, also The device is carrier unlocked. Why is that? although oem unlock is not there would i be able to flash to an earlier firmware to get the oem unlock option? And what the heck is CONN_GADGET?

Also trying to downgrade to bootloader v1 via odin G998USQU1AUA4. am i able to without bricking the phone?
 
Last edited:
sketchscarz

sketchscarz

Senior Member
Mar 2, 2011
229
95
Eugene
Verizon Samsung Galaxy S7
ZTE Blade V9
Am i able to flash magisk in twrp without bl unlock?
 

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HittinBottom

New member
Oct 22, 2021
2
0
Hello everyone, for a few months now (a day here or a day there) I've been struggling to root my Korean S21 with ZERO success. Can I get a some help/guidance please? Better yet, I'd gladly pay a reasonable fee to have this done for me.


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  • 29
    afaneh92
    afaneh92
    Note: this guide copied from topjohnwu's. Original guide here

    US/Canada bootloader unlock thread:
    here

    Before Installing Magisk
    • Installing Magisk WILL trip KNOX
    • Unlocking bootloader for the first time will do a data wipe.
    Installation

    If you already have Magisk installed, it is strongly recommended to upgrade directly via Magisk Manager using the “Direct Install” method. The following tutorial is only for initial installation.

    Getting Started

    Before you start:
    • This tutorial assumes you understand how to use adb and fastboot
    • If you plan to also install custom kernels, install it after Magisk
    • Your device’s bootloader has to be unlocked

    Download and install the latest Magisk app. In the home screen, you should see:

    device_info.png


    The result of Ramdisk determines whether your device has ramdisk in the boot partition.

    Unlocking Bootloader

    Unlocking BL on modern Samsung devices have some caveats, so I figure this would be helpful.
    • Allow bootloader unlocking in Developer options → OEM unlocking
    • Reboot to download mode: power off your device and press the download mode key combo for your device (Vol Down + Vol Up) while connected to usb.
    • Long press volume up to unlock the bootloader. This will wipe your data and automatically reboot.

    If you think the bootloader is fully unlocked, it is actually not! Samsung introduced VaultKeeper, meaning the bootloader will still reject any unofficial partitions before VaultKeeper explicitly allows it.
    • Go through the initial setup. Skip through all the steps since data will be wiped again later when we are installing Magisk. Connect the device to Internet during the setup.
    • Enable developer options, and confirm that the OEM unlocking option exists and is grayed out. This means the VaultKeeper service has unleashed the bootloader.
    • Your bootloader now accepts unofficial images in download mode.

    Patching Boot Image

    If your device has boot ramdisk, you need a copy of the boot.img

    Instructions
    • Use either Frija or Samloader to download the latest firmware zip of your device directly from Samsung servers.
    • Unzip the boot.img from AP and copy the file to your device.
    • Press the Install button in the Magisk card
    • Choose “Select and Patch a File” in method, and select the stock boot image
    • Magisk Manager will patch the image to [Internal Storage]/Download/magisk_patched.img.
    • Copy the patched image to your PC
    • Flash the patched boot image to your device.
      For most devices, reboot into fastboot mode and flash with command:
      fastboot flash boot /path/to/magisk_patched.img or
      Rename magisk_patched.img to boot.img and use 7zip to make flashable tar of your boot.img
      Reboot to download mode. Open Odin on your PC, and flash boot_patched.tar as AP.
    • Reboot and voila!

    Patching AP

    Instructions
    • Use either Frija or Samloader to download the latest firmware zip of your device directly from Samsung servers.
    • Unzip the firmware and copy the AP tar file to your device. It is normally named as AP_[device_model_sw_ver].tar.md5
    • Press the Install button in the Magisk card
    • Choose “Select and Patch a File” in method, and select the AP tar file
    • Magisk Manager will patch the whole firmware file to [Internal Storage]/Download/magisk_patched.tar
    • Start the installation, and copy the patched tar file to your PC using ADB:
      adb pull /sdcard/Download/magisk_patched_[random_strings].tar
      DO NOT USE MTP as it is known to corrupt large files.
    • Reboot to download mode. Open Odin on your PC, and flash magisk_patched.tar as AP, together with BL, CP, and CSC (NOT HOME_CSC because we want to wipe data) from the original firmware.
    • Your device should reboot automatically once Odin finished flashing. Agree to do a factory reset if asked.
    • Install the Magisk app you’ve already downloaded and launch the app. It should show a dialog asking for additional setup.
    • Let the app do its job and automatically reboot the device. Voila!

    Custom Recovery​

    Installing using custom recoveries such as TWRP is only possible if your device has boot ramdisk.

    Instructions
    • Download the Magisk APK
    • Rename the .apk file extension to .zip, for example: Magisk-v2*.*.apk → Magisk-v2*.*.zip. If you have trouble renaming the file extension (like on Windows), use a file manager on Android or the one included in TWRP to rename the file.
    • Flash the zip just like any other ordinary flashable zip.
    • Reboot and check whether the Magisk app is installed. If it isn’t installed automatically, manually install the APK.

    Thanks
    @topjohnwu for magisk and guide, If you appreciate his effort, show some love and support :)

    Donations
    https://www.patreon.com/topjohnwu
    https://www.paypal.me/topjohnwu
    View
    4
    Didgeridoohan
    Didgeridoohan
    The latest Magisk Canary release (21409) contains the fix needed for the S21 devices, yes (but being a Canary release there are of course other bugs).

    But, @afaneh92, since you're just copying @topjohnwu's installation instructions exactly, word for word, wouldn't it just have been easier to link to those instructions and let people know that Magisk Canary releases now can root the S21 Ultra (and maybe also warn people that the Canaries can be buggy)?
    View
    3
    afaneh92
    afaneh92
    US/Canada devices has no oem unlock toggle!
    Unlock service here

    How to get OEM Unlock option back for Non US/Canada device?
    1. Open the Settings app. Tap on General Management → Date and time.
    2. Use the toggle button to disable Automatic date and time.
    3. Set date option will be enabled now. Tap on it, and set the date to about 10-20 days earlier.
    4. Enable developer options.
    4.a Go to your device Settings.
    4.b Select ‘About phone’ » tap seven times on ‘Build number’.
    └ This will enable Developer options under Settings.
    4.c Go back to Settings » scroll down to the bottom and you’ll see Developer options menu.
    5. Open developer options (in the Settings app itself), and find the option called ‘Auto update system‘. Use the toggle button to disable it.
    6. Now, go back to the main screen of Setting, and then tap on Software update.
    7. Disable the option ‘Download updates automatically‘.
    8. Tap on ‘Download updates manually‘ option, but it will give you an error because of the wrong date, so it’s fine.
    9. Restart the device.
    10. Go to Settings > Developer options. The OEM unlock option should be enabled now.
    View
    3
    afaneh92
    afaneh92
    Boomorrow said:
    Thanks, but that doesn't apply to the S21 :coffee:
    Click to expand...
    Click to collapse
    Use latest magisk canary, I have rooted my S21 Ultra.
    View
    3
    cjrivera04
    cjrivera04
    joancolmenares said:
    I assume this will trip Knox right?
    Click to expand...
    Click to collapse
    Read the very first bullet, lol
    View

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