Don't know about the Note9 - But typically you have to go back to the latest Oreo build before Flashing the One UI beta - There should be an xda Thread that lists the different versions - It's a good idea to remove the external sd card when Flashing the Stock Firmware on your device with Odin - I know that some people who don't... As for your external sd card showing as being "corrupt" - Could be one of two things: a) Scan it with your Windows computer - See if it passes or if it is really corrupt (you probably already did this?). It may be possible to "scan & fix" but since you already formatted it all data will be lost. b) Sometimes good sd cards do go bad & you may just have to replace it..
thanks, I went back to arj7. I found the sd card corruption to be a known issue for note9(and s9 as well). Fixed by reformatting fat via PC and then reinsert.
Samsung members ask not working. I'm having to use my tablet.
Go back to ARJ7. Then sideload this: https://firmware.science/download?url=7159/1488/SS-N960USQU1ARJ7-to-S1ARJA-UP Then sideload this: https://firmware.science/download?url=7159/1488/SS-N960USQS1ARJA-to-U1CRLJ-UP
