I can't speak to the burned discs but I can say uNetbootin is worthless in my experience at making flash drives. I tried for a couple months on and off again in Windows and Debian. Used every program I could find, nothing worked. Finally found suggestion to use dd instead. Worked perfect and since is the only way I make bootable flash drives.
dd if=/path/to/iso of=/dev/sd? oflag=direct bs=1M
? is letter of usb stick. In my case it usually is sdg. Do not send it to sdg1 or any other specific partition. Just send it directly to the device and it works every single time. Although admittedly this requires hybrid iso's that are capable of booting usb in the first place.
first to find out which drive letter is your flash drive.