For an older computer which doesn't boot from external (e.g. USB) devices but will load OFW from floppy or a sacrificial disc partition, and which is then able to see an external USB-connected CD-ROM drive, is there a generic command to tell it to boot from a CD (containing e.g. Linux or Windows) or would this rely too heavily on BIOS facilities that are unavailable once OFW is running?
Alternatively, given probe-usb output of
USB2 devices: USB1 devices: /pci/usb@7,2/cdrom@0,0 /pci/usb@7,2/cdrom@0,0/disk
how can I best look at the media to determine the name of kernel, initrd etc., and subsequently convert those into boot-device, boot-file, ramdisk etc. parameters? I've tried dir /pci/usb@7,2/cdrom@0,0/disk@0:0 etc. but the disc spins for a while and then reports iso9660-file-system.
I'm trying to write this up to answer an FAQ on a private conferencing system I use.