I've been trying to install a bunch of PC's to drive a bunch of CNC machines. Linux, as expected, manages to mess things up. When booting from a USB stick I get "Not a com32r image". The hack below seems to work:
After some fiddling around with the syslinux config files and still not getting it to boot properly, I found a deceptively simple workaround for this: Just type "help" on the BOOT prompt, and when you get the help menu, just hit enter. The system will now boot!
Confirmed that this also works for me when booting a USB stick created by 10.10's USB creator.