- #U BOOT CONFIGURATION STEPS HOW TO#
- #U BOOT CONFIGURATION STEPS SERIAL#
- #U BOOT CONFIGURATION STEPS UPDATE#
With the information provided by this document, you are set to begin loading alternate kernels and filesystems onto EMAC hardware.
#U BOOT CONFIGURATION STEPS HOW TO#
You have also seen a brief description of how to create scripts for U-Boot. You have also seen how to copy an image from RAM to flash how to configure your system to boot from an image once it has been saved to flash is documented elsewhere (see Related Information, below). You have seen how to execute an image from RAM. In this article, you have seen how to load an image into RAM using U-Boot. U-Boot will execute all commands in the script line-by-line until the script has finished, at which point the U-boot prompt will be returned to the user. If the command is not recognized, use autoscr instead. Note that the U-Boot command source was not available on older versions of U-Boot. Note the use of the protect off all command, which is required to unlock the flash on some systems. The example below illustrates the commands used to program a new kernel image to a SoM-9260M module. The flinfo command can be used to display the addressing of available flash devices on the system.Īfter loading the image to RAM, the flash device should be erased followed by copying the image to the appropriate offset in the flash. 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.
#U BOOT CONFIGURATION STEPS SERIAL#
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.
#U BOOT CONFIGURATION STEPS UPDATE#
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. A TFTP server must be accessible on the local network.
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