Is it possible to boot a generic OS (not necessarily linux or windows) from USB by simply loading a live-CD image file?
Use case: one USB drive with custom MBR, one text configuration file and one or more liveCD images. On boot-up, the user selects one of the images and loads that generic OS.
DOS (MS-DOS, FreeDOS, DR-DOS, ...), Windows 95/98/ME and boot loaders (Syslinux, grub, grub4dos, gujin, gag, mbldr, ...) boots, other operating systems must be aware of the memory mapping.
With SuperGrub2Disk http://www.supergrubdisk.org/wiki/SuperGRUB2Disk you just have to add a iso file into a specific folder and it will automatically be added to the bootloader menu. But AFAIK it does currently not support the memdisk solution.
This isn't possible in the generic case. Once the OS loads, its kernel will look for a root filesystem somewhere, and the ISO isn't one of the usual places it will look (ie: a partition).
Use case: one USB drive with custom MBR, one text configuration file and one or more liveCD images. On boot-up, the user selects one of the images and loads that generic OS.