Information About Rom Monitor Software; Rom Monitor Upgrade And Downgrade Basics - Cisco CRS-1 - Carrier Routing System Router Getting Started Manual

Upgrading and Downgrading ROM Monitor
Software
This appendix describes how to upgrade or downgrade the ROM monitor software on a Cisco CRS-1
Series Carrier Routing System router (Cisco CRS-1 Series router).
Contents
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Information About ROM Monitor Software

Before upgrading or downgrading ROM monitor software, you should understand the following concept:
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ROM Monitor Upgrade and Downgrade Basics

The ROM monitor, which is also known as ROMMON, is a bootstrap program that initializes the
hardware and boots the Cisco IOS XR software when you power on or restart a Cisco CRS-1 Series
router. ROM monitor upgrades can be required to resolve software defects or to support new features.
Typically, ROM monitor upgrades are infrequent and are not required for every Cisco IOS XR software
upgrade.
Tip Information on operating the router in ROM monitor mode is provided in
Monitor Guide."
In the Cisco CRS-1 Series router, there are two copies of ROM monitor: ROMMONA and ROMMONB.
During power on, ROMMONA loads first. If ROMMONA detects the presence of ROMMONB, it checks
the compatibility and integrity of the ROMMONB code. If ROMMONB passes these tests, ROMMONA
passes control of the router to ROMMONB.
Information About ROM Monitor Software, page B-1
How to Upgrade or Downgrade ROM Monitor, page B-3
Configuration Examples for ROM Monitor Upgrades, page B-6
Additional References, page B-12
ROM Monitor Upgrade and Downgrade Basics, page B-1
A P P E N D I X
Cisco CRS-1 Series Carrier Routing System Getting Started Guide
B
Appendix A, "ROM
B-1