My brand new s21 ultra was remotely controlled to restart it, shut it down, enable both WiFi and Bluetooth, and generate weird sounds all automatically. I neither insert any SIM card nor install/ configure anything. It told me that this device is so unsecured! I don't know how should I do with this outstanding device!
Is it because of UWB? How can I disable it?
I bought it from local computer store.
I've followed your steps, but it doesn't boot into Download mode. The splash screen of booting which is Samsung Galaxy Powered by Knox keeps showing for about every 15 seconds. It seems looping. Once I released both volume down and power buttons, it boots normally into the Android system.
Is it a big issue happened?
I've also just tried booting into Recovery Mode by following instructions from Internet. It failed to get into Recovery Mode, but normally boot into Lockscreen. Additionally, there are 3 lines of text messages appeared at the bottom half of the screen which are:
back-up : fail
setup-wizard [ FINISH ]
Excuse me, what is it?
I'm worrying about this too. Not just simply bring the device to Samsung, but also need to contact with the local Internet shopping centre about this terrifying discovery.
you are going overparanoid with UWB, if someone is hacking you it is not on uwb at all XD
I don't get why you are not booting in donwload or recovery. Please do the following then:
Donwload the android debug packaging from google:
Once donwloaded if you are on windows put the folder platform-tools on your desktop.
Open the start menu and start tiping command, command prompt should pop up and run it as an administrator. From the command prompt type the following command: cd C:\Users\<yourname>\Desktop\platform-tools
Where yourname is your username, if you do not know what is yours go on your system disk (usually C), then users folders and look at the users inside, you should find yours.
Now take your phone (it has to be turned on) go into settings, info, build number and tap build number till it says dev options are enabled.
Plug the phone into your pc and from the developer options enable usb debug. Switch from the panel of the phone the control device from this phone to connected device (click it once), at that point it should ask you if you want to enable debug, if it does not type in the command prompt: adb devices
It will say not detected (plug and replug), unauthorised (plug and replug at this point it should ask whetether you want to debug), authorised (perfect).
Once attached and authorised type in the command prompt: adb reboot download
Now the device will boot into donwload mode and tell us the code of the know warranty void is it 0x0 or 0x1, if you could take a clear picture of the writings it would be better.
The phone hasn't been hacked.
If your phone had been hacked then others would have experienced this too. Hackers don't spend their days and nights hacking hardware/software just to turn lights on and off. They do it for financial reward!
Like I said, your phone is probably a return and most likely is still linked to the original buyers "lost phone" app where they are able to remote access it. Nobody here can help you, just return it!
I've had read the YouTube for the way of rebooting to Recovery Mode or Download Mode which are all simple. Like I said, my phone is problematic. But I don't have a Windows platform hardware beside me. I'll try to get one to see the said numbers.
Besides, I've been attached by MITM too. You couldn't believe what I've had just experienced.