@messayisto Thanks, Mate. So it needed two attempts to get it working again. I first tried the 0.5.1 Focal for UT 24.04 which also did not work. I ended up with the one for UT 20.04 which now runs smoothly.

@messayisto Could that be done in the terminal, there seem to be no option to downgrade via OpenStore itself?

@messayisto I can confirm that behaviour.

@MrT10001 SUCCESS! Following your instructions the upgrade went trough within a quarter of a hour and is now on UT 24.04 stable. The only issue on that way was that the UT installer recognized the devices variant "lito" as unknown, as mentioned in another recent thread. Ignoring that the installer worked perfectly. Thank you very much @MrT10001!

Anyone who can mark this topic as solved is encouraged to do that.

I am an owner of two mobile phones running UT. While the upgrade from UT 20.04 to 24.04 on the Xiaomi Poco X3 NFC was successful within a couple of minutes, the Oneplus N10 failed to boot and got stuck at the "bootloader is unlocked" screen. I have been waiting for a hour or so and tried two more times, but to no success.

As I plan to get the N10 back to life, I am not sure on how far I have to go back, remembering the installation process some months ago, when I had to install Oxygen 10.5.7 first to make sure, that the correct firmware is present. Do I have to flash Oxygen again, or is the firmware still on the device since UT 20.04 has been installed, so that I immediately could start the UB installer?

Furthermore I am not sure, if USB-Debugging is active by default, so that flashing is possible.

Is there anyone who could give me a helpful answer or advice? Thank you very much in advance!

Harry

@frifo Can you confirm to have installed the correct Qualcomm-drivers in advance before proceeding? As mentioned in another post: As BULK is shown in device manager it should be a sign for a missing or wrong driver installed.

Screenshot, made on 25-06-11, on a POCO X3 running UT 20.04 OTA-9.

Did not try If the Vietnamese keyboard really works, just remarked that the option is being offered.

Can not confirm that. When choosing the keyboard layout on top of the main screen you have to scroll all the long way down to find Vietnamese, which in this order is one of the last opportunities in that row being offered.

SUCCESS!
Hard to find out what's been the essential step. I just booted OxygenOs 10.5.7 this time with a SIM-card inserted and connected to WiFi immediately. Surprisingly now I could enable OEM-unlocking and after that "fastboot oem unlocked" without any issues.
UT 20.04 is running, so the device will be my daily companion from now on.

Thank you so much, mates!

Didn't find out to mark that thread as solved.

@davids
Another path to go. After flashing OxygenOS I've done an offline login procedure, so that might be another chance to try that one more time with wifi connected. Will report the result. Thank you very much.

@MrT10001
Thank you. I will check this. I suppose you suggest having "a valid internet connection" is meant on having that on pc, which I do have via ethernet. I had no SIM-card inserted, so put one in could be another attempt. IMEI ist present.

As my daily driver, a POCO X3 NFC, running UT 20.04, has been damaged, so I went for a refurbished OnePlus Nord N10 (BE2029).

Following the instructions given on the UP homepage I used MSMDownload tool and flashed OxygenOS 10.5.7 on that device successfully. Before that I could unlock the bootloader. After the successful flashing process the bootloader is locked again, so I can't go on any further to install UT on it. Unlocking via adb + fastboot methods won't work, returning "flashing unlock is not allowed". In developer options OEM-unlocking is greyed out and therefore can't be chosen.

On some forums I read the advice to mail to OnePlus itself to receive an unlocking code to re-unlock the bootloader again.

Is there anyone who could help, it would be very appreciated.