Refer to the documentation for your hardware for more information on the correct address ranges to use. Also, each image (U-Boot, bootstrap, kernel, filesystem) must be stored at the correct offset for the system to operate correctly. NOR flash is directly memory-mapped to the system at a physical address. This section explains the process of storing an image to non-volatile storage.Ī combination of the erase and cp commands are used to program an image to a NOR flash device. Many systems have more than one device, such as serial DataFlash and NAND flash. The process of copying an image from RAM to flash memory differs depending on what type of flash storage devices are available on the system. To update the bootcmd variable to download the image on each boot, simply replace the command used to load the image from flash with the TFTP download command. For example, after loading the kernel image above, running bootm 0x70000000 would boot the board using the new image without making any changes to the images stored on the flash. Furthermore, the boot command can be set such that the image is automatically downloaded and executed on each boot, making testing more efficient.Īfter loading a bootable image to RAM, you can execute it directly using the bootm command for a uImage kernel or bootz for a zImage kernel. This is especially helpful when testing new Linux kernel images. In some situations, it is advantageous to execute the image directly from RAM after loading with TFTP rather than saving to flash. Note that the filesize variable has been automatically updated to the size of the file that was loaded. The example below shows the use of DHCP and setting the TFTP server IP address to 192.168.2.1 Before continuing, determine a valid static network address for your local network contact your IT department for more information on what address to use if required. The network mask and broadcast address will be determined automatically from these settings, and no default gateway setting is required if the server is on the same subnetwork as the board. Typically, the IP address of the board and the IP address of the TFTP server are the only settings that need to be defined. Static networking configuration or DHCP can be used on some systems (requires DHCP server). In order to load a file using TFTP, U-Boot must be configured to access the local network. Please contact EMAC if you need details on how to use NFS instead of TFTP to load images. Information on how to set up an NFS server can be found here. Alternatively, NFS can be used in place of TFTP but will require an NFS server. The specific details of TFTP server setup and configuration can be found on the Installing TFTP server page. There is a separate wiki page about configuring LCD in U-Boot.A TFTP server must be accessible on the local network. The default environment has these values set as well. To get U-Boot output shown on the built-in framebuffer driver (currently, HDMI only at 1024x768), add the following to your boot.cmd: Note: on the A20 based cubieboards, this only seems to work on the stable kernel, not on stage. Recent version of U-Boot are able to boot from NFS as well as TFTP, but you have to get rid of the automatic setup of FTP. Setenv bootargs console=ttyS0,115200 root=/dev/mmcblk0p2 rootwait panic=10 create a file boot.cmd on the first partition (also check Kernel arguments for extra 'bootargs' options):.For getting these bits loaded onto the hardware, please refer to the respective howto:įor booting from sd with mainline u-boot, the recommended way is:
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