系统启动后，进入到

U-Boot>

后输入help，将显示所有支持的内置命令，如下所示

?       - alias for ‘help‘
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   - boot application image from memory
bootp   - boot image via network using BOOTP/TFTP protocol
bootz   - boot Linux zImage image from memory
chpart  - change active partition
cmp     - memory compare
coninfo - print console devices and information
cp      - memory copy
crc32   - checksum calculation
dfu     - Device Firmware Upgrade
dhcp    - boot image via network using DHCP/TFTP protocol
echo    - echo args to console
editenv - edit environment variable
env     - environment handling commands
exit    - exit script
ext4load- load binary file from a Ext4 filesystem
ext4ls  - list files in a directory (default /)
ext4write- create a file in the root directory
false   - do nothing, unsuccessfully
fatinfo - print information about filesystem
fatload - load binary file from a dos filesystem
fatls   - list files in a directory (default /)
fatwrite- write file into a dos filesystem
fdt     - flattened device tree utility commands
go      - start application at address ‘addr‘
help    - print command description/usage
imxtract- extract a part of a multi-image
itest   - return true/false on integer compare
loadb   - load binary file over serial line (kermit mode)
loady   - load binary file over serial line (ymodem mode)
loop    - infinite loop on address range
md      - memory display
mdio    - MDIO utility commands
mii     - MII utility commands
mm      - memory modify (auto-incrementing address)
mmc     - MMC sub system
mmcinfo - display MMC info
mtdparts- define flash/nand partitions
mtest   - simple RAM read/write test
mw      - memory write (fill)
nand    - NAND sub-system
nboot   - boot from NAND device
nfs     - boot image via network using NFS protocol
nm      - memory modify (constant address)
ping    - send ICMP ECHO_REQUEST to network host
printenv- print environment variables
reset   - Perform RESET of the CPU
run     - run commands in an environment variable
saveenv - save environment variables to persistent storage
setenv  - set environment variables
sf      - SPI flash sub-system
showvar - print local hushshell variables
sleep   - delay execution for some time
source  - run script from memory
test    - minimal test like /bin/sh
tftpboot- boot image via network using TFTP protocol
true    - do nothing, successfully
ubi     - ubi commands
ubifsload- load file from an UBIFS filesystem
ubifsls - list files in a directory
ubifsmount- mount UBIFS volume
ubifsumount- unmount UBIFS volume
usb     - USB sub-system
usbboot - boot from USB device
version - print monitor, compiler and linker version

Uboot支持的命令