I have tried many methods in the internet and every time I get a corrupted "burnt" USB image from the official "ubuntu-17.10-desktop-amd64.iso" file. The image either gets burned with 2048 bytes block size, instead of 512, or gets burned correctly (with 7_zip) but won't boot.
Even the official "Startup Disk Creator" won't do the job right.
I believe there is something wrong with the official file. PS: the SHA256SUM has been checked