用TTL线连接，停在redboot>，怎么刷固件？

wp583

Actiontec MI424-WR Rev.D用TTL线怎么刷OPENWRT？加电信息如下：
Error setting unicast address! 00:00:00:00:00:00

Trying NPE-B...no PHY found
Trying NPE-C...EthAcc: (Mac) cannot enable port 1, MAC address not set
can't enable port!
No network interfaces found

RedBoot(tm) bootstrap and debug environment [ROM]
Non-certified release, version Jose-2952 - built 21:46:45, May  3 2010

Copyright (C) 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009
Free Software Foundation, Inc.
RedBoot is free software, covered by the eCos license, derived from the
GNU General Public License. You are welcome to change it and/or distribute
copies of it under certain conditions. Under the license terms, RedBoot's
source code and full license terms must have been made available to you.
Redboot comes with ABSOLUTELY NO WARRANTY.

Platform: Actiontec MI424WR (IXP4XX) BE
RAM: 0x00000000-0x02000000 [0x00021838-0x01fc1000 available]
FLASH: 0x50000000-0x507fffff, 64 x 0x20000 blocks
RedBoot> fis load ramdisk
No image 'ramdisk' found
RedBoot>

wp583

用fconfig -i 设置IP还是ping不通，TFTP就用不了，用TTL线怎么传文件？