Just updated the Qualcomm DragonBoard 410c to (patched..) Kernel 4.2-rc5, from here:  https://git.linaro.org/landing-teams/working/qualcomm/kernel.git/shortlog/refs/heads/integration-linux-qcomlt

This time, the boot was successful, and the mmc1 SDcard (rootfs) was recognised correctly..

Fedora release 23 (Twenty Three)
Kernel 4.2.0-rc5 on an aarch64 (ttyMSM0)
.........
]# uname -a
Linux rg410c 4.2.0-rc5 #1 SMP PREEMPT Tue Aug 25 11:38:52 PDT 2015 aarch64 aarch64 aarch64 GNU/Linux

Now, if only this device supported UEFI booting, instead of the android-phone-like fastboot/flash process…!

Robert Gadsdon.  August 25, 2015.