#U boot tftp command software

The second command, dhcp, tells U-Boot to use DHCP to acquire an IP address.

Here, the first command, set autoload no, tells U-Boot not to try to load an image after they've gotten an IP address from the DHCP server.

Also see Executing kernel from RAM U-Boot> set autoload no The machine should now boot, and show output on its console as it does so.Īn alternate kernel can be loaded into memory temporarily and booted if the kernel is not already programmed in the flash or a development kernel is to be tested. Execute the next line to load and run the default kernel. If the kernel is already programmed into the flash, it can be used in most cases to boot into the NFS root filesystem. The nfsroot=10.0.0.20:/srv/nfs/test_filesystem directive tells Linux to look for an NFS server at 10.0.0.20 and to mount the /srv/nfs/test_filesystem directory as the root filesystem for the machine. The ip=dhcp directive tells Linux to acquire an IP address by requesting one from the DHCP server. The rootfstype=nfs directive tells Linux that the root filesystem is of the NFS variety. The root=/dev/nfs directive tells Linux to instantiate with the virtual device, /dev/nfs, as the root filesystem. U-Boot> setenv bootargs console=$ part tells Linux to use the console setting from the U-Boot environment variable this will usually be something along the lines of console=ttyS0,115200n8. Where XX should be replaced by your devices default debug UART. On initial use of U-boot the console variable should be set to the device's debug UART and buad rate, so kernel boot information can be displayed to the console. Set the bootargs variable to tell the kernel to boot into the NFS filesystem: The root filesystem does not have to be the directory shared by the NFS filesystem it can be in a subdirectory, which means many root filesystems can be shared by one NFS server.Ĭonfiguring the Client to Boot from NFS Configuring U-Boot The NFS server must be configured to allow clients to access this filesystem. This document assumes that the root filesystem for the board will be located at /srv/nfs/rootfs on the NFS server.įor more information on setting up an NFS server, see Setting up an NFS File Server.Ī complete root filesystem for the EMAC OE system to boot from must be stored on the NFS server.

This is often done using the /etc/exports file. Once the server has been installed, export a directory to use as the root filesystem. EMAC recommends using the nfs-kernel-server package available on most desktop Linux distributions if setting up a new NFS server.

#U boot tftp command software

This is often the same machine that is being used for software development. To boot an EMAC OE system over NFS, an NFS server must be available on the local network. For information on installing a TFTP server, see Installing TFTP server. Some prerequisites must be met prior to being able to boot a root filesystem over NFS.Ī TFTP server is required if a kernel image is not already programmed in flash. 2 Configuring the Client to Boot from NFS.