The preferred method in CentOS/RHEL 7 is to use good 'ol dd as explained here: https://wiki.centos.org/HowTos/InstallFromUSBkey Couldn't be easier - no fancy script necessary:
# dd if=ucs-c240-huu-3.0.4d.iso of=/dev/sdx
Please verify your USB drive assignment before using this command! Do not specify a partition number - just leave it as sdb, sdc or whatever.
... View more