@Balrong Uninstalling core apps is not advised as there is an issue reinstalling them. I would run the device through the installer again and leave the wipe data box unticked to resolve.

@MadDino Check here. Download the unlock.rar file (link still works). You don't need to root the device for UT. Follow these instructions and you need a Windows PC:

*DATA WILL BE WIPED SO MAKE A BACKUP

1. Download this zip(you already have) and you'll get 2 folders 'unlock' and drivers
   https://drive.google.com/open?id=1YpezCedaRWGDS9WW7UaXXyyBod0Bk5qp
2. Install the drivers and go the 'unlock' folder
3. Reboot your phone to fastboot mode by pressing volume up + power on at the same time.
4. Connect it to pc and open unlock.bat in 'unlock' folder
5. Done*

@rocket2nfinity fastboot reboot fastboot will put you to fastbootd and you cannot unlock the bootloader from there.

@hlbkv said:

but on connection it gets back to the generic gear icon.

That's normal restarting the Network Manager.

You can reinstall through the installer leaving the "wipe data" unticked which will retain all your data and take about 10 minutes or in updates change the channel to development and then back again.

@shengchieh It usually means the "OEM unlock" toggle in Developer options has not been set to enable. Other scenarios include old versions of ADB and fastboot on the PC, if in the US, no token .

@hlbkv Have you tried a reinstall?

@hlbkv Is it the TB-X306F or X? I haven't experienced this on Focal or Noble and I am running on Stable. I have seen this on other devices running development and it usually happens after sleep. Have you tried resetting it using network manager?

sudo systemctl restart NetworkManager

What is the device?

@shengchieh are you in the USA? The US devices seem to behave issues unlocking the bootloader. If not, have you enabled developer mode and enabled OEM unlocking there? Edit: I see you have, but double check. If you have downgraded the Android version it automatically relies the bootloader.

@Teasy Hi and welcome to the forums. You can try the update path through software updates on the tablet. The other way requires a Windows PC, the Lenovo Software fix Tool, the devices serial number and a USB cable to attach the device to the PC.

@sysadmin I know, but we all know the situation is complicated at the moment. I hope it gets better for all in the future. Work around have to do...

@sysadmin You could route wifi on the UT device through phone (ahem, Android or Apple) running a VPN as a workround. I know it will be difficult in Russia at the moment, those in charge may even block mirrors, official or community to get you using their apps...

@gus0000 put the device on stock ROM, Android version 9. Don't relock the bootloader. Unzip the vendor image. Use installer version 0.10.0.

@r0lle Had very few issues with installing on Pixel 3a/3a XL. If you get stuck on the Google logo instead of recovery, this may interest you....

@r0lle it is the installing of UT on the UT installer where you will see the check boxes.

@kugiigi Thats the problem, it is not worldwide, it is a countrywide thing and each country and in the US, states, have their own legislation that can impose fines through their own regulatory bodies for what is an infringement of their law. Apple have started a blanket implementation of age id on their latest iteration of iOS. You just have to look at what’s happening in Brazil over their compliance law (lots of gray areas). In the UK Imgur.com have region blocked the UK over the Internet safety Act and age compliance. Then there is Australia.....

There is a lot of naivety amongst politicians over the ramifications of these laws and I would not like to see Ubuntu Touch, let alone any open source project be sanctioned in a country that has decided it does not conform to their laws.

@developerbayman There are going to be many points of view on this and there are many new news articles appearing about this and the way different countries and in the US, states are approaching it. At the moment you have to be philosophical about it as you probably well know, that most of the users of devices will not be bothered and comply, otherwise their life becomes more awkward than it already is. Case in point is the UK's Internet Safety Act which created a massive uptake in VPN subscriptions. This has now caused the UK regulatory body Ofcom to starts "monitoring" this, wherever that is going to lead.
The long point though is this is the precursor to Government "Digital id" and I think we all know where that is going to go (Social Exclusion like certain countries, even 1984) but I think we will have to cross that bridge when digital id is enforced.
However the sad part is that it is going to stifle free thought and invention as non compliance is going to force out the free and free thinking innovators not tied to a Global corporation like Apple or Google due to local, state and countrywide sanctions for non-compliance or not being able to comply.
I am sure it has and will be discussed. I am sure legislators will be lobbied. What I am sure of though is most legislators will toe a line to comply to their political parties leanings and will fail to see the ramifications of what this will cause.

@makapaka Have you download and unzipped Android Platform tools?

If not, download the windows version, unzip it and open a terminal in that folder (right click and in the menu "open in terminal"). This will give you ADB and fastboot.

Power off the phone and boot to fastboot with Volume Down and Power button. Then connect it to the PC and run the fastboot devices command in that terminal.

Have you installed the Xiaomi USB drivers?

@makapaka Nah, not corrupted, just check in a terminal with the command fastboot devices. In fastboot mode you can install the fastboot ROM from here. I have done this on this device a few times. It takes some time so leave the device alone when flashing. Do NOT relock the bootloader as it can brick the device.

@formel No, I elevated the command prompt in windows Powershell using ./ and it has always worked so I have never used fastboot flashing unlock_critical on this device. Most of the times I have installed using Windows with no issues. Have you upgraded to Noble (24.04.1.x)?