How does UNetBootin format my flash drive?

I have been using UNetBootin to create bootable flash drives with the computer restore program redobackup((http://redobackup.org/) A linux based OS). This works fine with no errors. But if i try to copy the same file unetbootin just created onto a new flash drive it is not bootable, and gives me the error bootmngr missing.

Is their a simple, or difficult solution to easily copy these files created by UNetBootin onto new fresh flash drives. Then allow these new flash drives to also boot the same way the UNetBootin configures the flash drive.

What does UNetBootin do to the flash drive that I am not seeing file wise? I've attempted creating a primary partition for the new flash drive and setting it as active and keeping it as a FAT32 but this still gives me the error BootMngr missing. I've also attempted using syslinux but this will give me the error "com32 file menu.c32 is missing" when menu.c32 is in the correct directory, and not corrupt as far as I can see.