Set this variable to 0 boot without delay. During this time a countdown is printed, which can be interrupted by pressing any key. This command is only executed when the variable bootdelay is also defined!Īfter reset, U-Boot will wait this number of seconds before it executes the contents of the bootcmd variable. This variable defines a command string that is automatically executed when the initial countdown is not interrupted. The contents of this variable are passed to the Linux kernel as boot arguments (aka “command line”). If set to yes, an image loaded using the rarpb, bootp, dhcp, tftp, disk, or docb commands will be automatically started (by internally calling the bootm command).Ī decimal number that selects the console baudrate (in bps). If set to no (or any string beginning with 'n'), the rarpb, bootp or dhcp commands will perform only a configuration lookup from the BOOTP / DHCP server, but not try to load any image using TFTP. The location on the flash partition is predefined: package/uboot-ar71xx/files/include/configs/nbg460n.h for the Zyxel NBG 460N/550N/550NH. The environment variables are set up in a board specific file, e.g. The environment is usually at the end of the uboot partition. This flexibility is based on being able to easily change environment variables. One of the huge advantages of Das U-Boot is its ability for run time configuration. You can read and write these values when you are connected to the U-Boot console via Serial Port and also from the CLI once you booted OpenWrt. It stores some values like the IP address of the TFTP server (on your PC) to which the the TFTP client (part of U-Boot) will try to connect, etc. This can hardly be compared to NVRAM/TFFS-approach of other bootloaders. Das U-Boot uses a small amount of space on the flash storage usually on the same partition it is stored on to store some important configuration parameters.
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