U-Boot: Quick reference

This page provides quick U-Boot command reference. Please refer to the U-Boot project documentation for detailed descriptions of the features listed below. To get more information about a specific command, type help [command] in the U-Boot command line.

The actual command list depends on the U-Boot version, and the board configuration it was built for.

Information commands

• bdinfo - print Board Info structure
• coninfo - print console devices and information
• flinfo - print FLASH memory information
• help - print online help

Memory commands

• base - print or set address offset
• crc32 - checksum calculation
• cmp - memory compare
• cp - memory copy
• md - memory display
• mm - memory modify (auto incrementing)
• mtest - simple RAM test
• mw - memory write (fill)
• nm - memory modify (constant address)
• loop - infinite loop on address range

Flash memory commands

• cp - memory copy
• flinfo - print FLASH memory information
• erase - erase FLASH memory
• protect - enable or disable FLASH write protection

Image commands

• iminfo - print header information for application image
• imxtract - extract a part of a multi-image

Execution control commands

• autoscr - run script from memory
• source - run script from memory
• bootm - boot application image from memory
• go - start application at address 'addr'
• loop - infinite loop on address range
• exit - exit script

Download commands

• bootp - boot image via network using BOOTP/TFTP protocol
• dhcp - invoke DHCP client to obtain IP/boot params
• loadb - load binary file over serial line (kermit mode)
• loady - load binary file over serial line (ymodem mode)
• loads - load S?Record file over serial line
• rarpboot - boot image via network using RARP/TFTP protocol
• tftpboot - boot image via network using TFTP protocol
• nfs - boot image via network using NFS protocol
• ping - send ICMP ECHO REQUEST to network host

Environment variables commands

• env - environment handling commands
• editenv - edit environment variable
• printenv - print environment variables
• saveenv - save environment variables to persistent storage
• setenv - set environment variables
• run - run commands in an environment variable
• bootd - boot default, i.e., run 'bootcmd'
• boot - boot default, i.e., run 'bootcmd'

File system support commands

• fatinfo - print information about a FAT file system
• fatload - load binary file from a FAT file system
• fatls - list files in a FAT file system directory (default /)
• ext2load - load binary file from a Ext2 filesystem
• ext2ls - list files in a directory (default /)
• fsinfo - print information about JFFS2 file system
• fsload - load binary file from a JFFS2 file system image
• ls - list files in a JFFS2 file system directory (default /)

NAND flash support

• nand - NAND sub-system control
• nandecc - switch OMAP3 NAND ECC calculation algorithm
• nboot - boot from NAND device

Partition commands

• mtdparts - define flash/nand partitions
• chpart - change active partition

FDT support

• fdt - flattened device tree utility commands

MMC support

• mmc - MMC sub system
• mmcinfo - display MMC information

I2C support

• i2c - I2C sub-system control

USB support

• usb - USB sub-system control
• usbboot - boot from USB device

Cache support

• icache - enable or disable instruction cache
• dcache - enable or disable data cache

Bitmap support

• bmp - manipulate BMP image data

GPIO support

• gpio - manipulate gpios

Miscellaneous commands

• echo - echo arguments to console
• reset - Perform RESET of the CPU
• sleep - delay execution for some time
• version - print monitor version
• test - minimal test, like /bin/bash
• ? - alias for help
• showvar - print local hushshell variables
• true - do nothing, successfully
• false - do nothing, unsuccessfully
• cls - clear screen
• itest - return true/false on integer compare