It isn’t perfect - one step says “A blue transfer bar will appear on the device showing the recovery being transferred” and the next one says “With the device powered off,…”, when the device is in a state where pressing the power button does nothing.
Nevertheless I ended up with a working e/OS on the phone.
Sorry for not trying Open Android Installer. I just didn’t want to risk another failure after one “easy” installer failed on me.
Aha, so you have been introduced to Heimdall. I am happy for you that the installation was successful. Just like the Easy Installer, Open Android Installer guides you through the process, but I can understand you wanted to use the official guidelines. Anyway, for other custom ROM’s like /e/OS I can recommend Open Android Installer. Besides installing the OS, you can choose to install Google Apps (if you really wanted to) or MicroG, which mimicks the Google functionality. /e/OS has the latter preinstalled. Congrats!