This procedure assumes you are running on a PC running Ubuntu itself.
Do not power up the BBB until instructed.
1) Take a blank micro SD card 2GB or bigger and plug it into your laptop/desktop PC. I use Gparted to remove any existing partitions on this microSD card. Be sure you know which /dev/mmcblk0 or /dev/sd* is your micro SD card! For this procedure I will assume the SD card is at /dev/mmcblk0.
2) Download the *.img.xz file of your choice
As of this writing, Ubuntu 12.04, 14.04 and Debian 7.5 are available.
xz -cd ubuntu-*armhf*-bone*.img.xz > /dev/mmcblk0
This will take 5-10 minutes with a card writing at 5MB/sec.
exit to drop out of su mode (prompt is a $ instead of the su #).
sudo partprobe /dev/mmcblk06)
ls -al /dev/mmcblk0
sudo parted -l
you should see two partitions under /dev/mmcblk0 — the first partition, flagged “boot” will be about 1 megabyte in size. The second partition will be about 2 gigabytes in size with the ext4 file system.
sync to confirm that writing to SD card is complete. Then since you have not mounted the SD card (if you did, unmount it) pull the SD card out of your PC. Note that the micro SD card goes into the Beaglebone Black “upside down” with the contacts facing away from the PCB.
Booting up the BBB:
* You will need a microHDMI to HDMI (or DVI, VGA, etc.) adapter to plug into your existing monitor–or, you can choose to run entirely remotely over SSH.
* BE SURE TO PLUG AN ETHERNET CABLE into your network before booting.
* Now with the Ubuntu microSD card inserted into the BBB, hold down the user/boot switch (the one closest to the microSD card on the opposite side of the PCB) and keep holding after plugging in mini-USB and 5.5mm power until the third LED from the Ethernet jack starts flashing (indicating the microSD is being accessed).
* WAIT about 1 minute with a black screen (not suspended, but just black) screen while Ubuntu start. THen you’ll see “ubuntu-armhf login” with username: ubuntu
You now have a basic Ubuntu setup. Using
df -h reveals that <0.5GB is being used, which gives you the option of copying from SD to internal eMMC.
* don’t forget to change your password by typing
* install the useful parse-edid program by typing:
sudo apt-get install read-edid
After this first Ubuntu boot, you do NOT have to hold down user/boot switch on future bootups to use the SD card. Subsequent boots take me 12 seconds to get to login prompt (with Class 4 SD card (a slow crummy card)).
based off of: http://www.armhf.com/index.php/getting-started-with-ubuntu-img-file/