@herbert Well done, that’s a nice find. Your problem was puzzling me, I just hadn’t come up with any suggestions. I have heard that unetbootin has more recently been failing to write working boot keys for a number of linux distro’s so it’s good to have confirmation that it’s failing on Rockstor iso’s also. I know it use to be one of the “go to” iso to usb writer program but have never used it myself so don’t really know. We are planning on also adding ddrescue as a suggested usb key writer which has worked for me on the Rockstor iso’s. I heard of using ddrescue instead of dd from Martin Wimpress (co founder of Ubuntu Mate) on a podcast. They detail their suggested use of ddrescue on their download page at:-
https://ubuntu-mate.org/ .
Also good idea on adding to the docs so others might avoid your frustrations and benefit from your findings.
So that this isn’t forgotten I’ve created an issue in the rockstor-docs repository so it might be considered.
Cheers for persevering and sharing your findings.