1. Fetch a devicetree image

fetch https://builds.96boards.org/snapshots/dragonboard410c/linaro/ubuntu/latest/dt.img

1. You will need the Android fastboot utility available in the android-tools-fastboot package:

pkg install android-tools-fastboot

1. Follow the 96boards instruction to create an SD card with a rescue image. For example:

fetch 'http://builds.96boards.org/releases/dragonboard410c/linaro/rescue/latest/dragonboard410c_sdcard_rescue*.zip'
tar xvf dragonboard410c_sdcard_rescue\*.zip
sudo dd if=db410c_sd_rescue.img of=/dev/da0 bs=64k

Install the SD card and set the SD boot switch on the bottom of the DragonBoard to on and turn on the power.

1. Use fastboot to boot the image. Caution: /sbin/fastboot is a link to /sbin/reboot, so be sure that you execute the correct one!

/usr/local/bin/fastboot boot loader-qcomm.img

Consoles: Qualcomm console  
entry: 0x82001000 94000035 ffffff80007a1000
KDB: debugger backends: ddb
KDB: current backend: ddb
Copyright (c) 1992-2015 The FreeBSD Project.
Copyright (c) 1979, 1980, 1983, 1986, 1988, 1989, 1991, 1992, 1993, 1994
        The Regents of the University of California. All rights reserved.
FreeBSD is a registered trademark of The FreeBSD Foundation.
FreeBSD 11.0-CURRENT #376 2f77486(arm64-qcomm)-dirty: Wed Aug 19 14:49:30 BST 2015
    andrew@bender:/usr/obj/arm64.aarch64/usr/home/andrew/freebsd/repo/head-git/sys/GENERIC arm64
FreeBSD clang version 3.6.1 (tags/RELEASE_361/final 237755) 20150525
WARNING: WITNESS option enabled, expect reduced performance.
CPU(0): ARM Cortex-A53 r0p0
random: entropy device external interface
ACPI: Table initialisation failed: AE_NOT_FOUND
ACPI: Try disabling either ACPI or apic support.
ofwbus0: <Open Firmware Device Tree>
cpulist0: <Open Firmware CPU Group> on ofwbus0
cpu0: <Open Firmware CPU> on cpulist0
arm64_cpu0 on cpu0
arm64_cpu0: Found register: 0
cpu1: <Open Firmware CPU> on cpulist0
arm64_cpu1 on cpu1
arm64_cpu1: Found register: 1
cpu2: <Open Firmware CPU> on cpulist0
cpu3: <Open Firmware CPU> on cpulist0
pmu0: <Performance Monitoring Unit> irq 23 on ofwbus0
generic_timer0: <ARMv8 Generic Timer> irq 18,19,20,17 on ofwbus0
Timecounter "ARM MPCore Timecounter" frequency 19200000 Hz quality 1000
Event timer "ARM MPCore Eventtimer" frequency 19200000 Hz quality 1000
simplebus0: <Flattened device tree simple bus> on ofwbus0
uart0: <Qualcomm HSUART> mem 0x78b0000-0x78b01ff irq 140 on simplebus0
uart0: console (-1,n,8,1)
gic0: <ARM Generic Interrupt Controller> mem 0xb000000-0xb000fff,0xb002000-0xb002fff on simplebus0
gic0: pn 0x0, arch 0x2, rev 0x0, implementer 0x70 irqs 288
cryptosoft0: <software crypto>
Timecounters tick every 1.000 msec