当时是启动就进入了rommon模式，因为系统找不到引导文件，无法配置confreg 0x2102 / confreg 0x2142

只能通过以下步骤完成
rommon 1 >confreg
Configuration Summary :
=> load rom after netboot fails
=> console baud: 9600
=> autoboot from: commands specified in 'BOOT' environment variable
do you wish to change the configuration? y/n [n]: y
enable "diagnostic mode"? y/n [n]: y
enable "use net in IP bcast address"? y/n [n]: n
disable "load rom after netboot fails"? y/n [n]: y
enable "use all zero broadcast"? y/n [n]: n
enable "break/abort has effect"? y/n [n]: n
enable "ignore system config info"? y/n [n]: n
change console baud rate? y/n [n]: n
change the boot characteristics? y/n [n]: y
enter to boot:
0 = disable autoboot
1 = the first file from internal flash device
2 = commands specified in 'BOOT' environment variable
[2]: 1
Configuration Summary :
=> diagnostic mode
=> console baud: 9600
=> autoboot from: the first file from internal flash device
do you wish to save this configuration? y/n [n]: y
You must reset or power cycle for new configuration to take effect