How to unlock bootloader

frifo

When starting ubports-installer, it is written: "Before installing Ubuntu Touch you must unlock the bootloader of your phone manually. Folllow the steps in the linked page if you haven't already. More..."

On the linked page "https://community.oneplus.com/thread/64487" is written:

Download the full Android SDK here (scroll to the bottom of the page>DOWNLOAD FOR OTHER PLATFORMS>SDK Tools Only)
Extract the zip and place the android-sdk-windows folder on your desktop. ...

On the linked page "https://developer.android.com/studio?hl=en#download" there is no text "DOWNLOAD FOR OTHER PLATFORMS" and there is no text "SDK Tools Only".
At the bottom of the side are "SDK tools package" for Windows, Max and Linux for download. When I download the file for Windows: commandlinetools-win-13114758_latest.zip and unzip the file, the folder "comdline-tools" appears, which contains no folder "android-sdk-windows". Therefore it is not possible to place the folder "android-sdk-windows" on the desktop, because this folder doesn't exist.

MrT10001

@frifo download platform tools and extract it then copy the platform tools folder to somewhere you cand find it, i.e. the desktop and ope a command prompt in that folder ( right click command prompt in drop-down menu). Downgrade/upgrade the device to the required version of Android first as that will automatically lock the bootloader.

frifo

Extracting the ZIP-file delivers the folder cmdline-tools. I have placed this folder on the Desktop, opened the folder and started the terminal.

PS Directory: C:\Users[username]\Desktop\cmdline-tools> dir
bin
lib
NOTICE.txt
source.properties

PS Directory: C:\Users[username]\Desktop\cmdline-tools> cd platform-toolsadb
cd : The path "C:\Users[username]\Desktop\cmdline-tools\platform-toolsadb" cannot be found

I guess, commandlinetools-win-13114758_latest.zip is the wrong file.

frifo

On the linked page "https://community.oneplus.com/thread/64487" is written:

"5. To confirm that it is indeed working, open a command prompt window and enter the following commands:
cd Desktop/android-sdk-windows/platform-toolsadb versionIf it displays "Android Debug Bridge version x.x.xx" it is working. If it is gives an error saying that adb is not a recognized command, it has not been successful. Carefully repeat the steps above if this is the case. Close the command prompt window when you are done."

But the path "platform-toosdb" isn't included in the file commandlinetools-win-13114758_latest.zip.

MrT10001

@frifo Download platform tools from here.

Extract the folder to somewhere it is easy to find, open a command prompt in that folder by right clicking in an empty space, selecting the terminal program you have installed.

Then fastboot and ADB commands will work.

frifo

The file commandlinetools-win-13114758_latest.zip from the URL "https://developer.android.com/studio?hl=en#download" doesn't work, because it is the wrong file.
It seems, that the right URL is "https://developer.android.com/tools/releases/platform-tools?hl=de" and the file "platform-tools-latest-windows.zip".

When I unpack this file, go to the folder platform-tools, open the terminal and type
adb version
I get the response:
Android Debug Bridge version 1.0.32.

But when I start the phone in the fastboot (volume up + power) and after that pluging to the PC and write the command
fastboot devices
comes no response