[Samsung Galaxy S21 Ultra] x10forevers:
First of all, as you all know - you are responsible for anything that you do to your device, neither me nor anyone helping you are responsible for it. Of course this generous community will help you through if anything unexpected happens.

and just to make sure that you're not an idiot, this is for SAMSUNG phones only and only for S21 Series. YOU CAN TRY THIS METHOD ON OTHER SAMSUNG DEVICE BUT YOU WILL NEED UPDATE FILE OF ONE UI BETA 4 FOR THE DEVICE YOU TRYING TO FLASH

-- The process I am explaining and/or describing here is tested by me and it works 100%. I have Canadian S21ultra which is not part of the beta program, I tried to install beta update on Canadian firmware but it failed so I tried this method and I have successfully installed ONE UI 4 Beta and everything works. This should work with S21/S21+

This is a few steps process so read carefully through each and every step, I am gonna try to keep this as easy and noob friendly as possible, if you have any questions feel free to ask.

-- This process will take place in 4 parts so it doesn't get confusing, it needs to go in chronological order.

Step 1 : Download needed files and tools for your device

Step 2 : Backup your data

Step 3 : Flash current stable firmware for your device family either exynos or snapdragon via ODIN

Step 4 : Install One UI 4 Beta 1

Step 1 : Download needed files and tools

1. ODIN tool to flash the firmware (Search xda/Google for this)​

2. SDK Platform-tools from here SDK Platform-tools - once downloaded, extract files​

3. CURRENT stock firmware of the device (One UI 3.1) - This is the latest One UI 3.1 firmware from the country getting beta updates.​

- For Example : If you are installing UK One UI beta, Download Latest Stable One UI 3.1 firmware from UK which is compatible for your device (Please make sure it is the same processer as your current device, if you have exynos S21 device, download exynos and if you have snapdragon version download snapdragon one) -- you can download it from Galaxy Firmware Website or website or source of your choice.​

- Extract Firmware zip.​

4. Beta Update zip file - Copy this file in Platform-tools folder and rename it to update.zip if needed.​

Snapdragon Version : Click Here​

Exynos Version : Click Here​

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Step 2 : Backup your data (Recommended but not necessary)

1. Samsung smart switch for Computer -- From Here​

2. Samsung Cloud Backup - from settings of your device.​

3. Google Backup - from settings of your device.​

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Step 3 : Flash Current stable firmware corresponding of your device family either exynos or snapdragon via ODIN - This step will wipe all the data on your phone.

1. Open ODIN executable file (i.e. exe)​

2. Connect your phone in download mode to the computer via USB cable (Turn off your phone, while pressing volume up+down button, plug in the USB Cable to your computer, you will see teal screen with some disclaimers on your phone, press volume up)​

3. Click on BL on ODIN screen and navigate to the folder where you extracted firmware from step 1, click on file name starting with BL_xxx.tar.md5, wait for it to populate in ODIN. Repeat process with AP, CP and CSC (NOT HOME_CSC) in ODIN (AP will take a lot of time to load so grab a coffee/bear/Tea or whatever you like while that processes).​

4. Click start and wait for that to be finished​

5. You will see success in ODIN and your device will reboot to the system​

6. Turn off your device by pressing power button once its booted.​

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Step 4 : Install One UI Beta 1 update

1. Boot your phone into recovery by continue pressing power and volume up button, once you see the samsung logo release both buttons.​

2. Select Install update from adb​

3. Open platform-tools on your Computer, hold shift and right click - select open command prompt here.​

4. write adb sideload update.zip​

5. Wait till the process finished.​

6. Power On your phone by pressing power buttons and your device should boot into One UI 4 Beta.​

7. Follow on-screen instruction to set-up your phone.​

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