uBoot

mmcinfo
ext2ls mmc 0:1 /boot

setenv bootdelay 5
setenv bootargs 'console=ttymxc0,115200 root=/dev/mmcblk0p1 rootwait rw panic=5'
setenv bootcmd 'ext2load mmc 0:1 0x70800000 /boot/${uname_r}/uImage; ext2load mmc 0:1 0x71000000 /boot/${uname_r}/imx53-usbarmory.dtb; bootm 0x70800000 - 0x71000000'
saveenv

setenv bootargs "${bootargs} ${bootargs_disk} ${bootargs_debug}"

boot

It is possible to load a kernel over the SerialConsole using the xmodem or ymodem protocols.

=> loady                                                                                                                         
## Ready for binary (ymodem) download to 0x72000000 at 115200 bps...
Csum mode, 15419(SOH)/0(STX)/0(CAN) packets, 13 retries
## Total Size      = 0x001e1c50 = 1973328 Bytes
=> bootm
## Booting kernel from Legacy Image at 72000000 ...
   Image Name:   Linux-3.16.2
   Image Type:   ARM Linux Kernel Image (uncompressed)
   Data Size:    1973264 Bytes = 1.9 MiB
   Load Address: 70008000
   Entry Point:  70008000
   Verifying Checksum ... OK
   Loading Kernel Image ... OK

Starting kernel ...

uBoot's env tools now support reading and writing settings from MMC; a suitable version of fw_printenv can be cross compiled with `env ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf- make env`. The resulting `fw_printenv` tool can be copied into userland and symlinked to `fw_setenv`; buildroot does this correctly. This is the required configuration file

root@usbarmory:~# cat /etc/fw_env.config 
# Device name    NVRAM offset    Env. size
/dev/mmcblk0     0x60000         0x2000