I've burned this image with Etcher on a USB stick: $ sha1sum pop-os_18.04_amd64_intel_40.iso b874efcd2dbbe81b91e9e4cc04c6a3ccb60b25da pop-os_18.04_amd64_intel_40.iso When I attempt to boot my Lenovo X1 Carbon 6th gen from it, I get this error: 