Passwords in bash scripts

With the recent updates and or changes in Linux, I found my old method of using:
 yes "${Password}" | passwd "${Username}" 
within chroot for assigning passwords in bash scripts no longer works. Seems this is possibly by design for security concerns from what I can tell.

Through some searching, reading and testing, I came up with a nice passwd replacement of chpasswd. chpasswd is part of the shadow package, which is an Arch base package. The man page on chpasswd reveals an -R option. This seems a perfect fit for my use case.

-R, --root CHROOT_DIR
           Apply changes in the CHROOT_DIR directory and use the configuration files from the CHROOT_DIR directory.

In my latest install script, I used chpasswd as a replacement for passwd:

 URN=jeff    ## Username      ##
 URP=test    ## User Password ##
 RTP=test    ## Root Password ##

 arch-chroot /mnt useradd -m -g users -G wheel -s /bin/bash "${URN}"
 echo "${URN}:${URP}" | chpasswd -R /mnt
 echo "root:${RTP}" | chpasswd -R /mnt

Note: The passwd --stdin option has been removed from current shadow 4.6-1 available in Arch.