今天遇到了一个很奇怪的事情，上电后，isr4400无法加载image，查看了一下bootflash，发现又是好的，image也是存在的而且size也是完好无损，断电、reset都试过了，每次都是直接进入rommon。
1. 检车bootflash文件系统是否完好。 结果是好的 rommon 4 > dir bootflash: File System: EXT2/EXT3 11 16384 drwx------ lost+found 811201 4096 drwxrwxrwx .prst_sync 12 89328 -rw-r--r-- bgp-pns-ovld1.config 14 1752 -rw-r--r-- bgp-pns-ovld1.clean 827425 4096 drwxrwxrwx .installer 227137 4096 drwxr-xr-x core 64897 4096 drwxr-xr-x .rollback_timer 13 0 -rw------- tracelogs.874 648961 229376 drwxrwxrwx tracelogs 18 2151 -rw-r--r-- crdc-config 730081 4096 drwxrwx--- vman_fdb 21 98207 -rw-r--r-- test 275809 4096 drwxr-xr-x quit

2. unset BOOT, 让路由器自己去选择image rommon 1 > unset BOOT rommon 2 > set PS1=rommon ! >  MCP_STARTUP_TRACEFLAGS=00000000:00000000 RET_2_RTS= EULA_ACCEPTED=TRUE CRASHINFO=crashinfo_FAILED TFTP_FILE=bzImage.SSA.bin IP_ADDRESS=10.75.167.164 IP_SUBNET_MASK=255.255.255.0 DEFAULT_GATEWAY=10.75.167.1 TFTP_SERVER=10.74.9.48 THRPUT=2000000 LICENSE_BOOT_LEVEL=appxk9,appxk9:esg;uck9,uck9:esg;securityk9,securityk9:esg; BSI=0 RANDOM_NUM=958801295 RET_2_RCALTS=1406805522 ?=0 rommon 3 > sync rommon 4 > reset Resetting ....... Initializing Hardware ... System integrity status: 00000610 Rom image verified correctly System Bootstrap, Version 12.2(20130621:100325) [dgreeson-15_3_3R_S 101], DEVELOPMENT SOFTWARE Copyright (c) 1994-2013  by cisco Systems, Inc. Compiled Fri 06/21/2013  6:12:33.26 by dgreeson Current image running: Boot ROM0 Last reset cause: PowerCycleRequest Cisco ISR4451/K9 platform with 4194304 Kbytes of main memory rommon 1 > set
原因就是，硬件工程师调试板卡的时候，把config register更改了，直接进入rommon，启动diag。 比较有意思的是，不能直接把confreg更改成2102，而必须是先更改成2142，然后更改成2102.
Resetting ....... Initializing Hardware ... System integrity status: 00000610 Rom image verified correctly System Bootstrap, Version 12.2(20130621:100325) [dgreeson-15_3_3R_S 101], DEVELOPMENT SOFTWARE Copyright (c) 1994-2013 by cisco Systems, Inc. Compiled Fri 06/21/2013 6:12:33.26 by dgreeson Current image running: Boot ROM0 Last reset cause: PowerCycleRequest Cisco ISR4451/K9 platform with 4194304 Kbytes of main memory rommon 1 > set PS1=rommon ! > MCP_STARTUP_TRACEFLAGS=00000000:00000000 RET_2_RTS= EULA_ACCEPTED=TRUE CRASHINFO=crashinfo_FAILED TFTP_FILE=bzImage.SSA.bin IP_ADDRESS=10.75.167.164 IP_SUBNET_MASK=255.255.255.0 DEFAULT_GATEWAY=10.75.167.1 TFTP_SERVER=10.74.9.48 THRPUT=2000000 LICENSE_BOOT_LEVEL=appxk9,appxk9:esg;uck9,uck9:esg;securityk9,securityk9:esg; BSI=0 RANDOM_NUM=958801295 RET_2_RCALTS=1406805522 ?=0 confreg=0X2102 rommon 2 > ? alias set and display aliases command boot boot up an external process break set/show/clear the breakpoint confreg configuration register utility context display the context of a loaded image cookie display contents of cookie PROM in hex dev list the device table dir list files in file system dis display instruction stream frame print out a selected stack frame help monitor builtin command help history monitor command history meminfo main memory information repeat repeat a monitor command reset system reset set display the monitor variables showmon display currently selected ROM monitor stack produce a stack trace sync write monitor environment to NVRAM sysret print out info from last system return token display board's unique token identifier tsec print out info from the ethernet driver unalias unset an alias unset unset a monitor variable rommon 3 > confreg 0x2102 monitor: command "confreg 0x2102" not found rommon 4 > " not found monitor: command " rommon 5 > confreg 0x2142 You must reset or power cycle for new config to take effect rommon 6 > reset Resetting ....... Initializing Hardware ... System integrity status: 00000610 Rom image verified correctly System Bootstrap, Version 12.2(20130621:100325) [dgreeson-15_3_3R_S 101], DEVELOPMENT SOFTWARE Copyright (c) 1994-2013 by cisco Systems, Inc. Compiled Fri 06/21/2013 6:12:33.26 by dgreeson Current image running: Boot ROM0 Last reset cause: PowerCycleRequest Cisco ISR4451/K9 platform with 4194304 Kbytes of main memory no valid BOOT image found Final autoboot attempt from default boot device... File size is 0x00015cf0 Located bgp-pns-ovld1.config Image size 89328 inode num 12, bks cnt 22 blk size 8*512