Changes

 [[:Category:U-Boot|U-Boot]] is used to boot the Linux kernel and by setting some environment variables it's possible to select how to perform the boot process. The default U-boot environment provides two boot configurations that are explained in more detail in the following sections.

This configuration is conceived for standalone operation. Both the kernel and the root file system are retrieved from Flash. Once U-Boot has transferred the control to Linux, its job is completed. From now on Linux kernel has the control of the hardware. At the end of Linux boot process, the user can interact with the system with the typical Unix-like shell through the same serial connection used for U-Boot. To run this configuration just issue the command  <pre>run flash_self.</pre>

If your system does not match this configuration, just change the necessary variables and store them permanently with the u-boot <pre>setenv/saveenv </pre> commands.  To run this configuration just issue the command

To run this configuration just issue the command <pre>run net_nfs.</pre>

If you wish Lizard system to automatically boot with one of the above configurations, just set up and store the <pre>bootcmd </pre> variable. For example, for the <pre>flash_self </pre> configuration, issue the following commands:=<pre> setenv setenv bootcmd $({flash_self)}=> setenv serverip 192.168.0.72saveenv=</pre> saveenv

Next time the system boots, U-Boot will wait for three seconds (to stop the wait just press any key in the console) before executing the commands stored in the <pre>bootcmd </pre> variable. This time can be changed by setting the <pre>bootdelay </pre> variable. Generally speaking the whole boot process can be further and heavily customized. For more details please refer to the doc/README.autoboot file in the U-Boot sources.