U-boot command reference


U-Boot commands supported by the default AVR32 U-Boot shipped with STK1000 and Network Gateway

Command list

askenv <variable>get environment variables from stdin


askenv bootarg
base print or set address offset
bdinfo print Board Info structure
boot boot default, i.e., run 'bootcmd'
bootd boot default, i.e., run 'bootcmd'
bootm <addr> [arg]boot Linux kernel loaded (with dhcp,tftp,fsload or ext2load) to address. pass arg to kernel.

By default bootm will use arguments specified by environment variable bootargs example:

bootm 0x90400000
bootp boot image via network using BootP/TFTP protocol
cmp.b <addr1> <addr2> <count> memory compare byte wise


cmp 0x00 0x20000000 0x2000 

will compare the 8k first bytes of flash to the 8k first bytes of sdram.

cmp.w <addr1> <addr2> <count>memory compare word wise
coninfo print console devices and information
cp.b <addr1> <addr2> <count> memory copy byte wise


cp.b 0x20000000 0x00 0x2000 

will copy 8k bytes from sdram to flash.

cp.w <addr1> <addr2> <count> memory copy word wise


cp.w 0x20000000 0x00 0x2000

will copy 8k WORDS (16k bytes) from sdram to flash.

crc32 checksum calculation
dhcp [<addr> [filename]] invoke DHCP client to obtain IP/boot params

Without parameters, it will obtain an ip address and load the file specified by the environment variable bootfile from tftp into sdram at location addr. example:

dhcp 0x90400000 uImage
echo echo args to console
erase all erase FLASH memory
erase <start> <end> erase FLASH memory from sector containing address start to sector containing end


erase 0x20000 0x7F0000
erase <start> +>len> erase FLASH memory from sector containing address start to start+len
ext2load <interface> <dev[:part]> [addr] [filename]load binary file filename from a Ext2 filesystem located at device dev into memory address addr


ext2load mmc 0:1 0x90400000 uImage
ext2ls <interface> <dev[:part]> [directory] list files in directory (default /) on ext2 filesystem located at device dev.


ext2ls mmc 0:1 /root
fsinfo print information about filesystems
fsload [addr] [filename] load binary file from a jffs2 flash file system


fsload 0x90400000 uImage
go start application at address 'addr'
help print online help
loadb load binary file over serial line (kermit mode)
loads load S-Record file over serial line
loop infinite loop on address range
ls list files in a directory (default /)
md memory display
mm memory modify (auto-incrementing)
mmcinit init mmc card
mtest simple RAM test (will not work on FLASH!!)
mw memory write (fill)
nm memory modify (constant address)
printenvprint environment variables
protect <on/off> [addr/all] enable or disable FLASH write protection


protect off 0x00 0x100
protect off 0x00 +0x100
protect on all
rarpboot boot image via network using RARP/TFTP protocol
reset Perform RESET of the CPU
run run commands in an environment variable
saveenv save environment variables to persistent storage
setenv <variable> <value> set environment variables


setenv bootarg 'console=ttyS0'

(note that there is no '=' between variable and value

sleep delay execution for some time
tftp [<addr> [filename]]Load file from tftp server into memory at <addr>


tftp 0x90400000 uImage

You will need to set the ipaddr and ethact environment variables before calling tftp.

The dhcp command will set ipaddr and ethact variables as obtained from your DHCP server and automatically call tftp.

tftpbootboot image via network using TFTP protocol
version print monitor version

Environment variables

variabledefault valuedescription
baudrate115200Communication speed
bootargsconsole=ttyS0 root=/dev/mtdblock1 rootfstype=jffs2Arguments to pass to Linux kernel
bootcmdfsload;bootmcommands to execute after the boot delay (if not aborted by hitting space) Multiple commands can be separated with a semi-colon.
bootdelay1Timeout in seconds before executing bootcmd
ethactmacb0Default Ethernet MAC, for use with tftp booting
ethaddr*Physical address for first MAC. Depending on serial number
eth1addr*Physical address for second MAC. Depending on serial number
ipaddr*Own IP Address (default set by dhcp call)
serverip10.191.252.181IP Address to server.
tftpip10.191.252.181IP Address to server for retrieving bootfile over TFTP.