I just thought I'd create a little post on the chance it may save someone a bit of time if in a similar situation to what I was in when I installed the Beta OS which caused issues to my device. Because it was a firmware issue, after all usual routes of repair failed, my only option was to completely reinstall the OS Firmware.
Please - only do this as a last resort and don't forget to create a backup of your device first!
*Don't forget that this will void any warranty as this a non-authorised software alteration.
First of all, on a Windows PC, you need to install the Samsung USB drivers. They can be found here:
Just locate your device model and select the download button on device software.
Next you also need to install an archive of the latest Samsung Firmware for your device. You can either Google search for Samsung Firmware downloadsor or you can follow this link to the site I used to download mine:
When you've downloaded all resources, extract the contents of the downloaded firmware folder into a safe location on your computer.
Next you need to connect your device to your computer via the USB cable. Once connected you then need to put your device into Download mode. This may vary between different devices but for my device (S20 Ultra 5G) I held volume down and power together. When the phone goes off and vibrates, let go of power keeping hold of volume down until the download mode screen appears. Press volume up to confirm putting the device into download mode.
Open Odin and your device should be shown. Click each of the parts listed as BL, AP, CP and CSC and navigate to where you extracted the firmware contents and select the relevant file for each one.
*Note the CSC will completely wipe the device so if its preferred that data is saved select the Home_CSC file.
Remember to tick the checkboxes also to the left of each option.
Click start and wait for the installation to finish.
Once completed, you can disconnect your device from the computer and your phone will be reset with the fresh firmware you just installed.
** please be aware that if you do this, you do so at your own risk and I will not be at fault if for whatever reason you do something wrong. If you're unsure of what to do or not confident then please take your device for professional repair.