4351 Router boot Loop

The methods to bring router up with correct Cisco IOS-XE image do not work.

Solution

This is the correct process to recover this infinite boot loop issue:

1. Break router into ROMMON mode with break sequence while you boot-up:

USE ctrl + C on booting of router to boot into Rommon

rommon 1 >

2. Change the config-register vlaue to 0x0 to ignore the boot variable configured in startup config:

rommon 1 > confreg 0x0

You must reset or power cycle for new config to take effect:

rommon 2 > reset

3. This brings the router into ROMMON mode again. Then change the config-register value to 0x2102:

rommon 3 > confreg 0x2102

4. Now you need to configure the correct boot variable from ROMMON:

Make sure you are using correct IOS version in your command.
rommon 4 > boot bootflash:isr4400-universalkx.xx.xx.xx.xxx.SPA.bin

Once router is up, you can delete the incorrect boot variable and configure the correct Cisco IOS-XE release:

Make sure you are using correct IOS version in your command.
ROUTER(config)#no boot system flash bootflash:isr4300-universalk9.03.13.01.S.154-3.S1-ext.SPA.bin
ROUTER(config)#boot system flash bootflash:isr4400-universalk9.03.15.01.S.155-2.S1-std.SPA.bin

Make sure you are using correct IOS version in your command.

5. Save the changes:

ROUTER#write memory