Hi, Lee wrote: > [...] I'd spin my wheels trying to > figure out what's wrong and not too much later say f*kkit and boot off > my just written USB drive. > [...] > $ check_debian_iso SHA512SUMS debian-12.7.0-amd64-netinst.iso /dev/sdb > ... > 661651456 bytes (662 MB, 631 MiB) copied, 7.11874 s, 92.9 MB/s > MISMATCH: '/dev/sdb' checksum differs from 'debian-12.7.0-amd64-netinst.iso' > in 'SHA512SUMS' > [...] > $ check_debian_iso SHA512SUMS debian-12.7.0-amd64-netinst.iso > ... > 661651456 bytes (662 MB, 631 MiB) copied, 2.65785 s, 249 MB/s > Ok: 'debian-12.7.0-amd64-netinst.iso' matches > 'debian-12.7.0-amd64-netinst.iso' in 'SHA512SUMS'
The script correctly truncated the data stream from /dev/sdb to the size that it read from the superblock of its ISO filesystem. If the checksums do not match, then some bytes in that range on /dev/sdb are not as they are in debian-12.7.0-amd64-netinst.iso. If you are interested in learning where, please keep the stick as it is now. Especially do not mount its EFI partition and do not plug it into a running MS-Windows system, which would happily alter bytes in that partition. The ISO contains a file /md5sum.txt with MD5 checksums for most of the files in the ISO. Although MD5 is nowadays easy to counterfei, it still is a useful transport checksum. For using that file, i choose two file names which suit me: mountpoint=/mnt/iso report_file=/tmp/md5_report and mount the ISO filesystem. You would probably do: sudo mount /dev/sdb "$mountpoint" I let md5sum verify the listed files cd "$mountpoint" md5sum -c ./md5sum.txt >"$report_file" 2>&1 Finally i look into "$report_file" by a text editor view "$report_file" I search for lines which end by the text snipped ": FAILED". My report file from debian-12.6.0-amd64-netinst.iso instead of /dev/sdb shows one failure, to my surprise: ./boot/grub/efi.img: FAILED That's the file which holds the EFI partition. I must have played with it. The sha256sum result with the .iso file does not match the one in https://cdimage.debian.org/mirror/cdimage/archive/12.6.0/amd64/iso-cd/SHA256SUMS any more. So i download debian-12.7.0-amd64-netinst.iso, check its SHA256, and repeat above check procedure. This time no lines with ": FAILED" at their end. Have a nice day :) Thomas
