Hi, Tom Browder wrote: > As I > understand it, I believe I can just copy the Debian CD live iso image file > onto the USB and it will be found and booted from fine.
Not necessarily. The question is: found by what ? The computer's firmware (BIOS or EFI, i assume) will ignore such an ISO 9660 image file in any filesystem. So you would need some bootloader or EFI tool to (kindof) mount the ISO image and to start the Linux kernel with initrd and appropriate options. The Debian ISOs for "i386" and "amd64" are prepared for being copied flatly onto USB sticks. This overwrites the partition table and BIOS boot code by bytes at the start of the ISO which take over those jobs. See https://www.debian.org/CD/faq/#write-usb or a bit more elaborate with backup of the stick's old state https://wiki.syslinux.org/wiki/index.php?title=Isohybrid#Copying_onto_USB_stick_by_shell_commands > 2. If a straight copy works as in question 1, is there any problem with > adding other files on the USB? The partition table of the ISO image is intended for booting the ISO, not so much for creating more partitions for other payload. It is possible, though. If you have more USB sticks at hand, use one for the ISO and the others for extra data. Else remove the GPT debris and create a new MBR partition as proposed in https://lists.debian.org/debian-user/2019/01/msg00568.html This does not answer the question which filesystem to install in the new partition. Something that can be mounted read-write on GNU/Linux and on MS-Windows, obviously. Just try and be prepared to try again. Have a nice day :) Thomas