I've got 2 USB sticks, an 8GB one for the installation ISO, and a 128GB one that I have installed Debian onto.
I sat for 30-45 minutes waiting for Debian to finish installing onto the 128GB flash drive, it did successfully, then it booted to it. I had to go to work so I shut everything down and left. When I came back and attempted to boot to the flash drive, it just won't. No GRUB boot loader, nothing failing, it just won't boot to it. I just had Debian dual booted on my SSD until I formatted it to go back to just Windows.
ASUS Motherboard (Maximus VII Formula if you need that part)
Idk if you need any of that, but any info could help.
I don't understand why I was able to boot to it at one point, but now I'm not able to.
** I've gone to Google, tried searching here, can't find anything that's been helpful.
*** I reinstalled Debian onto the flash drive, I was able to boot to it twice until I unplugged it, booted to Windows, plugged it back in and attempted to boot to it again.