Troubleshoot 4000 Series ISR for Issues with ROMMON

Introduction

This document describes how to recover the Cisco 4000 series ISR from ROMMON when configured with Cisco IOS®-XE release of an incorrect platform.

Background Information

This document describes step-by-step process on how to troubleshoot and recover Cisco 4000 series ISR (Integrated Services Router) from ROMMON or infinite boot loop if configured with Cisco IOS-XE release of incorrect platform. At times Cisco 4000 series ISR gets stuck in ROMMON or continuous boot loop.

Problem

Cisco 4400 and Cisco 4300 series routers have Cisco IOS-XE images that look very similar. If you configured the Cisco 4400 with a Cisco IOS-XE release for Cisco 4300, or vice-versa, the router does not boot up completely; rather, it gets stuck in ROMMON.

This is a Cisco 4400 configured with an Cisco IOS-XE release of Cisco 4300:

Router Specifications

• Cisco ISR4431/K9 (1RU) processor with 1665895K/6147K bytes of memory.
• Processor board ID: XXXXXXXXXX
• 4 Gigabit Ethernet interfaces
• 32768K bytes of non-volatile configuration memory.
• 4194304K bytes of physical memory.
• 7057407K bytes of flash memory at bootflash:.
• 4013055K bytes of USB flash at usb1

Example configuration leading to the issue:

ROUTER# conf t
Enter configuration commands, one per line. End with CNTL/Z.
ROUTER(config)# boot system flash bootflash:isr4300-universalk9.3.13.01.S.154-3.S1-ext.SPA.bin
ROUTER(config)# end
ROUTER#
ROUTER# show running-config | include boot

If you reload this router, the router gets stuck in ROMMON mode with this message on boot-up:

%IOSXEBOOT-1-INVALID_IMAGE: (RP/0): Booting an invalid ISR4300 image - Reloading system.

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

Troubleshooting Steps (Alternative Methods)

1. Try to bring router up with an USB Flash:

   rommon 1 > boot usb1:isr4400-universalk9.03.15.01.S.155-2.S1-std.SPA.bin

   Please reset before you reboot:

   rommon 2 > reset

2. Try to ignore startup-config and bring router up without startup configuration:

   rommon 3 > confreg 0x2142

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

   rommon 4 > boot usb1:isr4400-universalk9.03.15.01.S.155-2.S1-std.SPA.bin

   You need to reset before you boot:

   rommon 5 > reset

3. Try to bring router up from traditional bootflash file system:

   rommon 6 > boot bootflash:isr4400-universalk9.03.15.01.S.155-2.S1-std.SPA.bin

   Reset before you continue:

   rommon 7 > reset

4. In some cases, the internal bootflash file system is not recognized by the router:

   rommon 8 > dir bootflash:

   Reset before you continue:

   rommon 9 > reset

Solution

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

1. Break router into ROMMON mode with a break sequence while you boot-up.
2. Change the config-register value 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:

   rommon 4 > boot bootflash:isr4400-universalk9.03.15.01.S.155-2.S1-std.SPA.bin

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

   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

5. Save the changes:

   ROUTER#write memory

For the password recovery guide for the Cisco 4000 Series Integrated Services Router, refer to the Troubleshoot Guide for the Cisco 4000 Series Integrated Services Router.

Related Information

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