• Introducing XDA Computing: Discussion zones for Hardware, Software, and more!    Check it out!

General Samsung S21, S21+, and S21 Ultra U1 Firmware (Links)

Search This thread


New member
Nov 11, 2021
Hello. Admittendly I am a newbie here (as the badge to the left says.) I have been reading a few posts about flashing my S21 Ultra from Verizon to Unlocked in an attempt to get the calling and texting feature enabled. I realize this will not unlock my simcard and that is still controlled by Verizon, but will flashing my phone to the Unlocked firmware allow me to use the calling and texting feature?

Thank you.


Senior Member
May 10, 2010
Hi guys, i have a SM-G991Q, it's the Olympic athlete edition, Snapdragon, single SIM tray. Updates are delayed and I'd like to flash a compatible unlocked unbranded firmware.
Is this achievable?
Which firmware/version would you recommend?

Thanks in advance to everyone who will take the time to answer.
Last edited:


May 27, 2019
Whats the correctly unlocked U1 firmware for Galaxy S21 5G? I have at&t and I don't want AT&T bloatware

Top Liked Posts

  • There are no posts matching your filters.
  • 6
    After looking really hard ahead of launch for the U1 S21 Ultra Firmware using Samfirm and Frija, I couldn't find the US XAA firmware. Well I finally got a hold of it ahead of launch. You can use this firmware to flash any carrier branded S21, S21+, and S21 Ultra to U1 after receiving your device using Odin. Attached are the Google Drive links I've uploaded for your convenience. Links will be updated on a monthly basis for simplicity. Below is a simple guide on to flash this.

    Step 1: Download patched Odin and Firmware for the model that corresponds to your device's model number
    Patched Odin link:
    Download patched Odin and your phones firmware to an area on your computer that will be easy to access.

    If you do not have a program that can open rar files, then Winrar is a great program. Download link here

    Step 2: Download Samsung Smart Switch and make a complete backup of your entire device. Data will be wiped during this process, so make sure you have a complete backup.
    If Samsung Smart Switch says your device has an update, DO NOT UPDATE USING SMART SWITCH!
    Windows Link here: https://www.samsung.com/global/download/smartswitchwin/

    Step 3: Once your device is done backing up, Power off your device and put your device in download mode by pressing the Volume down button and power button at the same time. If you have done it correctly, your device should show this screen.

    Image Credit: Technastic.com

    Step 4: Connect your device to your computer and open up Odin.

    Step 5: Once Odin is opened, make sure your device is showing as connected, then select AP, and find your firmware file that you had extracted earlier, and select the one that says AP_(Your phones model), and do the same for every other one. So BL for BL, CP for CP, CSC for CSC, and USERDATA for USERDATA. Make sure you select the HOME CSC.

    Step 6: Click start. It will start to flash your U1 Firmware. Take a Tea break or something. Once its finished, it will automatically reboot.

    Step 7: Once device reboots, sign into your Gmail account you used previously, as well as your Samsung account. Once its at the home screen, restore the backup you made using Smart Switch and then once that completes, sign into all your apps. Your done. All OTA's now ill be XAA Samsung OTA's, not carrier branded ones.

    Step 8: Profit>?

    (S21 Firmware) SM-G991U1 Firmware - https://drive.google.com/file/d/1Vcwzg6FJxEw9G7OWob_Y7bgMzYKHijfG/view?usp=sharing
    (S21+ 5G Firmware) SM-G996U1 Firmware - https://drive.google.com/file/d/198TEeuqGdxI_6JgyzvyQ4DyoMX5IGfRc/view?usp=sharing
    (S21 Ultra Firmware) SM-G998U1 Firmware - https://drive.google.com/file/d/1xKTAURxnGZTXQLI4yRM39mo2zixslkHr/view?usp=sharing

    Enjoy and Happy Flashing
    Paypal Donation Link

    Questions and Answers

    Will this work for the Exynos version of the S21?
    No The provided firmware files are for the Snapdragon version. This might be compatible with the HK Snapdragon version, but I am not sure.

    Help, Odin won't flash, gives me an error.
    Respond in the comments below, and I'm sure we can get this to work.

    Will this unlock my phone from my carrier?

    No. If your device is locked before you flash this, it will be locked after you flash it. This is to remove carrier bloat and ensure all further updates will come from Samsung instead of your carrier. If you flash it before you unlock, you can still unlock your device as normal.

    I have bootloader unlocked my device, will this relock my bootloader?
    Yes. This includes the V2 bootloader for the S21 series, and as a result, if you flash this, you will lose your unlock token.

    Updated for May 2021 Security patches.
    are these the QUALCOMM Versions?
    Yes. US U1 firmware
    will this work with the T-Mobile version?
    This will work with any carrier branded version. It will entirely convert it from the carrier bloated version, to the U1 unlocked, Samsung version.
    FYI - I found new firmware that includes February Security Patch for G998U1 - you can download it here: February Firmware for Galaxy S21 Ultra

    the firmware is for a region labeled as ACG (not sure who this is - but I do know that the firmware works on my ATT S21 Ultra with no problems)

    Hope this is helpful -