Your Electra One controller should now be recognized as a USB disk named “ELECTRA” on your computer.
It’s “4,0 GB Volume” on Ubuntu, but this is just a minor thing.
Copy the “Controller-vx.x.x.srec” file that you downloaded in step 1 to the “boot” folder on the Electra One disk.
Can’t do, because of a permissions problem. It is strange because I seem to have permissions for the entire folder. Here is a screenshot of the permissions for the boot subfolder:
I’m not sure how to proceed and I’m not going to experiment with the E1 firmware folder. I thought I’d rather ask.
(Also note that the section title “Download the latest firmware file” is repeated in sections 1 and 2.)