DENX U-Boot及Linux使用手册

   Image Type:   PowerPC Linux Kernel Image (gzip compressed)

   Data Size:    605429 Bytes = 591 kB = 0 MB

   Load Address: 00000000

   Entry Point:  00000000

   Verifying Checksum ... OK

=>

    跟其它很多命令一样，imi命令的精确操作可由U-Boot的一些环境变量控制（这儿的是变量verify）。参见后面的详细介绍。

5.9.1.5  help – 显示在线帮助

=> help help

help [command ...]

    - show help information (for 'command')

'help' prints online help for the monitor commands.

 Without arguments, it prints a short usage message for all commands.

 To get detailed help information for specific commands you can type

'help' with one or more command names as arguments.

 =>

    help指令（简写为h或者?）显示在线帮助。如果不加任何参数，它会打印出所有当前U-Boot可用命令列表。你可以把某一指令名作为help的参数来获得这一命令的具体信息。比如：

=> help protect

protect on  start end

    - protect FLASH from addr 'start' to addr 'end'

protect on  N:SF[-SL]

    - protect sectors SF-SL in FLASH bank # N

protect on  bank N

    - protect FLASH bank # N

protect on  all

    - protect all FLASH banks

protect off start end

    - make FLASH from addr 'start' to addr 'end' writable

protect off N:SF[-SL]

    - make sectors SF-SL writable in FLASH bank # N