Then, when executing the .bat I got this error message:
Removing the battery didn’t work, so I looked online and the issue is fixed by executing the “fastboot flashing unlock” command
For that you need fastboot installed… But if you followed the guide you already have it! Just open a command prompt inside the downloaded folder “bin-msys” subfolder, and you can execute the command:
This command actually is part of the guide you linked to, in “Follow all the steps in the article Manage the Bootloader to unlock your bootloader.”
I see a possible problem for Linux users in that a big bold header there says “Part 2: On your computer (Windows and macOS)”, while this part applies to Linux, too, and clearly says so in the text. (@anna_jopp : This seems to need fixing?)
.bat is the file extension for Windows batch scripts and the terminal looks like Windows command prompt, so likely not due to the minor Linux misinformation.
Good point, I was too quick to go by the “$” prompt and the use of “./” in the second screenshot, which would be unusual on Windows, but the first screenshot clearly says “MinGW on Windows” .
Sorry if the post wasn’t clear, I just wanted to point out that the required tools (adb, fastboot, etc) are already downloaded in that specific scenario, in case someone installed e/OS and afterwards moved back to stock.