U-BOOT1.3.4 Nand Flash识别问题

问题很简单，但是不知道怎么下手，希望高手能够指点一二！


1.UBOOT启动后，在识别NAND时(如下绿色的256MiB ) 显得非常慢，大概要等上1~3秒钟，不知道是哪里出了问题！

U-Boot 1.3.4 (Nov 20 2012 - 22:42:53)

DRAM:  64 MB

Flash:  2 MB

NAND:  256 MiB

In:    serial

Out:   serial

Err:   serial

USB slave is enable!

dm9000 i/o: 0x20000300, id: 0x90000a46

DM9000: running in 16 bit mode

MAC: 08:00:3e:26:0a:5b

operating at unknown: 0 mode

Hit any key to stop autoboot:  0

2.命令tftp必须改成tftpboot才能使用TFTP下载。原来的tftp命令不知道飞哪里去了。

ARM2440 # help nand
nand info                  - show available NAND devices
nand device [dev]     - show or set current device
nand read[.jffs2]     - addr off|partition size
nand write[.jffs2]    - addr off|partition size - read/write `size' bytes starting
    at offset `off' to/from memory address `addr'
nand erase [clean] [off size] - erase `size' bytes from
    offset `off' (entire device if not specified)
nand bad - show bad blocks
nand dump[.oob] off - dump page
nand scrub - really clean NAND erasing bad blocks (UNSAFE)
nand markbad off - mark bad block at offset (UNSAFE)
nand biterr off - make a bit error at offset (UNSAFE)
nand lock [tight] [status] - bring nand to lock state or display locked pages
nand unlock [offset] [size] - unlock section

ARM2440 # help tftp
Unknown command 'tftp' - try 'help' without arguments for list of all known commands

ARM2440 # help tftpboot
tftpboot [loadAddress] [[hostIPaddr:]bootfilename]

ARM2440 #

怎么没人能解决呢        纠结啦           这个问题我研究了半月之久了