Hi, It might be too late for some, but I have really been struggling with this and finally succeeded. Just posting this in case somebody else faces the same problem, with a bit of luck they can find it all (or at least most of it) here. Note that it is not a detailed guide as I tried so many things, but it should give the overall gist of it.
I am new to both Hassio/OS and Linux so had to go through a lot of posts. This one somehow led me on the right track so I am posting here. I, like others did not want to run it on a linux/docker (yes, I know, many arguments for doing that, but I did not want to deal with that).
First problem was that most posts are about loading the hassio image to SD, which I do not have, some then resort to burning it directly to the SSD/HDD which I also could not do. So wanted to do it from USB. As others have encountered next problem was to get it to boot from USB, played around with bios settings, a lot. The main thing is to change USB from legacy to UEIF. I believe not everybody has to do that, but I had.
Once I got it to boot, the third problem was that the Hass installation got stuck, as other have, on the menu with autoboot, system 0, system 1, shell options. Neither of which worked.
Saw somewhere the description of a Linux Live distribution, where you run Linux from your USB. Tried that. Worked fine. Then some were talking about having the hass image on a nas server, a second USB and god knows what. Sounded very complicated. I put the gz file on the same USB as the Linux live. Then followed xbmcnut’s description (see post above): gunzip -c /home/ubuntu/Downloads/hassos_intel-nuc-2.12.img.gz | sudo dd of=/dev/sda
Problem four: As I was new to Linux I had no idea how/where to enter the above command. Turns out it is in a terminal window which you can open by pressing Ctrl + Alt + T. Probably obvious to Linux people, but not to me.
xmbcnut’s post might actually be what gave me the clue as he writes, offhandedly sort of, that BerryClaim “had downloaded the GZ using a live Ubuntu install instead”. And I had seen somewhere else that a live linux was running it from USB.
At some point during the above I had to put the USB back to legacy, not sure when that was, so play around with it.
So a big thanks to xmbcnut and the many others whose posts allowed me to piece this together.