I have a Galaxy S20 UW on Xfinity Mobile that just updated to One UI 3 / Android 11.
The upgrade has absolutely destroyed the split screen / multitasking capabilities. I've had the firmware flashed by a Samsung Care person, and he told me reversion is impossible, but intense googling says that user @CHMultimedia might be able to help.
No, it was Volume Down. You're in Fastboot (Vol. Up). But it's okay, all you have to do from there is to select Reboot to Bootloader (navigate with volume buttons, select with Power). Once the teal Downloading screen appears, you plug your phone and hit Start.
Oh sorry, they changed something. Alright, just Power Off, then hold Volume Up and Down simultaneously for a few seconds, then plug your phone to your PC while still holding both buttons. You should land on the teal warning screen, so now you must let go of the buttons. Dismiss it and then you can hit Start on Odin.
I ended up having to do a factory reset to get it to boot after the update but goddamn, it worked and it's ok because I SmartSwitched it first. I'm literally in tears, you've given me my phone back.
What other platforms are you on, so I can point other lost souls to you in the future?
I'm glad your device is now functioning but you should go disable the Software Update app ASAP, otherwise your phone will eventually check for updates and will force you to install Android R again. I'll give you instructions on that shortly.
I still come here once in a while so you can refer people that need help to Samsung Members Canada. Alternatively, they can go to http://chmulti.ca and they should use my Contact form or consult the upcoming documentation on my blog. I know this sounds like self-promotion but I have no ads on my website and I do not have any kind of sponsorship, so I have absolutely zero monetary incentive here.
Sorry that you still had to factory reset it, I know that flashing on some US carrier variants can be a bit complicated. It still worked and you had the foresight to backup your data in a responsible manner so no harm done, right? Enjoy your S20 UWB again!
Just a reminder. If you feel that someone has given you useful information, it's appreciated to "like" their posts. If you feel that someone has provided you with a solution, you can always click on the 3 dots & accept their help as a solution. You certainly don't have to, but it is appreciated & accepting their post as a solution can help others with the same questions.
