Loop mount does not accept offset= parameter, at least not for the values I tried:
mount -o loop,offset=1048576 -t ext4 rhel6-w1.img mnt
mount: rhel6-w1.img: failed to setup loop device: Numerical result out of range
Rebuilding util-linux-2.23.2-16.el7.src.rpm with added upstream commit a7d5202b5e49b7e33336818e00d240b8badddbb7 ("losetup: don't require 512-byte aligned offsets") fixes the problem for me.
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.
For information on the advisory, and where to find the updated
files, follow the link below.
If the solution does not work for you, open a new bug report.