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我有Am-1808板（evm放大工具包），現在我的ubl和uboot在spi flash中，並且文件系統和內核（uImage）在SD卡，我遵循在am-1808板上運行linux的步驟here：從usb代替sd卡在am-1808上啓動Linux（arago）
我沒有找到任何可以解釋從usb引導linux的官方參考/文檔，有可能我可以將文件系統+內核在USB中，然後告訴UBoot尋找USB從U盤找到UImage而不是SD卡。如果是，那麼你能解釋一下嗎？
的u-boot的代碼查找的uImage從SD卡的部分是：
#define CONFIG_BOOTARGS "mem=32M console=ttyS2,115200n8 root=/dev/mmcblk0p2 rw rootwait ip=off"
#define CONFIG_BOOTCOMMAND "if mmc rescan 0; then if fatload mmc 0 0xc0600000 boot.scr; then source 0xc0600000; else fatload mmc 0 0xc0700000 uImage; bootm c0700000; fi; else sf probe 0; sf read 0xc0700000 0x80000 0x220000; bootm 0xc0700000; fi"
我需要使用USB而不是SD卡的用於放置文件系統+的uImage，因爲我不得不使用SD卡銷（mmc0）用於其他目的。
更新：
This解釋引導從USB Linux的，但問題是，u-boot的不承認 'USB' 命令，當我鍵入：USB復位，它給了我這個錯誤：
U-Boot > usb reset
Unknown command 'usb' - try 'help'
'usb'命令也不出現在'help'命令顯示的可用命令列表中。
U-Boot > help
? - alias for 'help'
askenv - get environment variables from stdin
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
cmp - memory compare
coninfo - print console devices and information
cp - memory copy
crc32 - checksum calculation
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
ext2load- load binary file from a Ext2 filesystem
ext2ls - list files in a directory (default /)
false - do nothing, unsuccessfully
fatinfo - print information about filesystem
fatload - load binary file from a dos filesystem
fatls - list files in a directory (default /)
go - start application at address 'addr'
help - print command description/usage
iminfo - print header information for application image
imxtract- extract a part of a multi-image
itest - return true/false on integer compare
loadb - load binary file over serial line (kermit mode)
loads - load S-Record file over serial line
loady - load binary file over serial line (ymodem mode)
loop - infinite loop on address range
md - memory display
mdc - memory display cyclic
mii - MII utility commands
mm - memory modify (auto-incrementing address)
mmc - MMC sub system
mmcinfo - display MMC info
mtest - simple RAM read/write test
mw - memory write (fill)
mwc - memory write cyclic
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
saves - save S-Record file over serial line
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
sspi - SPI utility command
test - minimal test like /bin/sh
tftpboot- boot image via network using TFTP protocol
true - do nothing, successfully
version - print monitor version
任何想法如何可以在u-boot中指定'usb'命令？我是否需要將uboot升級到更新的版本？
問候
烏薩馬·本
這將主要取決於有一個版本的u-boot這對於您的特定平臺的USB主機驅動程序，並且是與他們建立啓用。 –
是啊，我解決了這個問題，爲我的開發板下載了新的uboot源代碼（升級版本），它已經啓用了usb。 – uyaseen