How to boot a board from a SD card
From RidgeRun Developer Connection
In this section it will be shown how to boot your file system directly from your SD card. For this tutorial the free SDK for the LeopardBoard DM365 but in most of SDKs you will find similar options.
1. First you must get a SD Card and format it with a software tool like gParted with the EXT3 system type.
2. Introduce your SD card on your SD card reader and copy all the files allocated in <DEVDIR_ROOT>/fs/fs/ to it.
3. Enter the configuration menu of your SDK (make config), go to File system configuration and select the Secure digital card from the File system image target menu.
4. Run the make command and then make install.
5. Start your board and stop it on the U-Boot prompt. Type printenv and copy the bootargs variable.
6. In this variable will be a parameter root= that will have no arguments. Set it as root=/dev/mmcblk0p1 and modify your bootargs line as is shown below
setenv bootargs '[...] root=/dev/mmcblk0p1 rootdelay=2 rootfstype=ext3 [...]'
7. Execute the previous line on your U-Boot prompt and then type saveenv.
8. Run the boot command and wait while your board starts.