In Cisco networking equipment, the ROM Monitor (ROMMON) is the low-level bootstrap firmware that resides on the router's hardware. The naming convention of the file follows a standardized pattern:
The ROMMON upgrade process, while generally straightforward using the upgrade rom-monitor filename command, requires patience and potentially multiple reload cycles to complete successfully. When issues arise, the Cisco support community and bug search tools provide valuable troubleshooting resources for resolving upgrade failures and compatibility problems.
If you are operating a dual-RP modular chassis (such as an ASR 1006 with dual RP2s), upgrade both slots to prevent a firmware mismatch during failovers:
Document the active ROMMON version to confirm whether an upgrade is necessary. Router# show platform | include ROMMON Use code with caution. asr1000-rommon.173-1r.spa.pkg
Do not power cycle, reset, or interrupt the router while the upgrade command is running. Doing so can corrupt the primary boot ROM and require an RMA. Step 4: Verify the Upgraded Boot Image
upgrade rom-monitor filename bootflash:asr1000-rommon.173-1r.SPA.pkg all Use code with caution. Copied to clipboard
Router# upgrade rom-monitor filename bootflash:asr1000-rommon.173-1r.spa.pkg slot R0 Use code with caution. In Cisco networking equipment, the ROM Monitor (ROMMON)
Remember: In routing, reliability starts before the first line of IOS-XE code executes. It starts in ROMMON.
Note: Exact commands vary by platform and current boot state; consult the Cisco ROMMON upgrade guide and package-specific release notes.
Upgrading the ROMMON firmware is not just about keeping software up to date; it directly impacts system availability and security. Bug Fixes and Stability If you are operating a dual-RP modular chassis
Run the following command to check your current hardware model and existing ROMMON version: Router# show platform Use code with caution.
Before upgrading, check your current ROMMON version:
The system will verify the code signature and upgrade the Route Processor (RP), Embedded Service Processor (ESP), and SPA Interface Processor (SIP). The upgrade process writes a new image to the ROMMON partition and typically takes around 8 minutes to complete.
Save the running configuration to an external TFTP/SFTP server.