Setting up your sdcard and u-boot's uEnv.txt for Beaglebone Black

gistfile1.txt

# Find your micro SD card using lsblk - you're going to want to set your DISK parameter to it.

export DISK=/dev/mmcblk0
sudo dd if=/dev/zero of=${DISK} bs=1M count=16

sudo sfdisk --in-order --Linux --unit M ${DISK} <<-__EOF__
1,48,0xE,*
,,,-
__EOF__


# If using mmcblkX or similar - you need the partition so...
sudo mkfs.vfat -F 16 ${DISK}p1 -n boot
sudo mkfs.ext4 ${DISK}p2 -L rootfs
 
# If your disk is set to the more traditional /dev/sdX use
sudo mkfs.vfat -F 16 ${DISK}1 -n boot
sudo mkfs.ext4 ${DISK}2 -L rootfs

sudo mkdir -p /media/boot/
sudo mkdir -p /media/rootfs/
 
# Again, for DISK=/dev/mmcblk0
sudo mount ${DISK}p1 /media/boot/
sudo mount ${DISK}p2 /media/rootfs/
 
# Or for DISK=/dev/sdX
sudo mount ${DISK}1 /media/boot/
sudo mount ${DISK}2 /media/rootfs/

sudo cp -v /path/to/u-boot/MLO /media/boot/
sudo cp -v /path/to/u-boot/u-boot.img /media/boot/

# You'll want to create a uEnv.txt to enable TFTP loading...
sudo vim /media/boot/uEnv.txt
ipaddr=10.0.0.3 
serverip=10.0.0.1 
kernel_file=zImage
console=ttyO0,115200n8
loadzimage=tftp ${loadaddr} ${kernel_file}
loadfdt=tftp ${fdtaddr} ${fdtfile}
my_bootargs=setenv bootargs console=${console} ${optargs}
uenvcmd=run loadzimage; run loadfdt; run my_bootargs; bootz ${loadaddr} - ${fdtaddr}

# Copy across your kernel and Device Tree
sudo mkdir -p /media/rootfs/boot
sudo cp -v /path/to/kernel/arch/arm/boot/zImage /media/rootfs/boot/
sudo cp -v /path/to/kernel/arch/arm/boot/dts/am335x-boneblack.dtb /media/rootfs/boot/


# Setup for NFS
ipaddr=10.0.0.3 
serverip=10.0.0.1 
kernel_file=zImage
console=ttyO0,115200n8
loadzimage=tftp ${loadaddr} ${kernel_file}
loadfdt=tftp ${fdtaddr} ${fdtfile}
my_bootargs=setenv bootargs console=${console} ${optargs} root=/dev/nfs rw nfsroot=${serverip}:/home/fedora/rootdir ip=${ipaddr}:::::eth0
uenvcmd=run loadzimage; run loadfdt; run my_bootargs; bootz ${loadaddr} - ${fdtaddr}

# Setup for booting from MMC
kernel_file=zImage
bootdir=/boot
mmcdev=1
mmcpart=2
loadzimage=load mmc ${mmcdev}:${mmcpart} ${loadaddr} ${bootdir}/${kernel_file} 
loadfdt=load mmc ${mmcdev}:${mmcpart} ${fdtaddr} ${bootdir}/${fdtfile} 
console=ttyO0,115200n8
mmcroot=/dev/mmcblk0p2 ro
mmcrootfstype=ext4 rootwait fixrtc
mmcargs=setenv bootargs console=${console} root=${mmcroot} rootfstype=${mmcrootfstype} ${optargs}
uenvcmd=run loadzimage; run loadfdt; run mmcargs; bootz ${loadaddr} - ${fdtaddr}