I recently got a 64GB USB stick and planned to make it a system repair multitool, with different live images and linux and windows installers, but I seem to have found a USB stick that just can't be booted from.
Pendrive Linux' Yumi installer doesn't recognise it, and only lists it when "show all devices" is activated.
The Windows 7 USB install tool doesn't recognise it either.
When putting an image on it with either Yumi or diskpart and xcopy, none of the three PCs I tested can boot from it, but none of them have problems booting from my small and slow 8GB stick. The HP USB format tool, as mentioned in this answer does format it, but that doesn't change anything. I tried both NTFS and FAT32, neither work.
What can possibly cause this? I always was under the impression that USB sticks are nothing but storage (like optical discs) and that it was enough to have to correct files on them to make them bootable. Could the controller inside the stick actively prevent this?
The mainboards of the PCs are the GA-MA770T-UD3 (AM3 socket, probably a bit old), the GA-Q87TN (1150 socket), and whatever is inside the Dell XPS12 9Q33. The latter two run Haswell processors with UEFI, I can't imagine that a 64GB stick would pose a problem.
I also tried formatting with the Windows tools, and tried to make a partition of only 20GB.