Always perform ROMMON upgrades via a direct console connection. SSH or Telnet sessions will disconnect during the mandatory router reboot.
Look for a string indicating version 17.3(1r)SG or equivalent microcode timestamping.
(Exact command syntax can vary by ROMMON and IOS‑XE version; refer to device CLI documentation.)
ROMMON is a bootstrap program that initializes the router hardware and boots the Cisco IOS XE operating system. It provides a command-line interface for low-level troubleshooting, password recovery, and booting images from alternative sources like USB or TFTP when the primary operating system fails to load. Key Features of ROMMON 17.3(1r)SPA asr1000-rommon.173-1r.spa.pkg
Cisco Bug: CSCwa12192 - ASR1k 17.3(1r) ROMMON upgrade may cause module to go to "disabled" state. Cisco Bug: CSCwa12192. ASR1k 17. ASR1002-X Upgrade version path - Cisco Community
High-density, compact service routers.
: Required to run Cisco IOS XE Amsterdam (17.3.x) and subsequent software releases seamlessly. Always perform ROMMON upgrades via a direct console
If you are managing a standalone router or a high-availability pair running Share public link
(Alternatively, you can also use show rom-monitor slot R0 to see specific software levels). ⚡ Best Practices & Warnings
The ROM Monitor (ROMMON) is the bootstrap program that initializes the hardware and boots the Cisco IOS XE operating system on Cisco Aggregation Services Routers (ASR) 1000 Series. Upgrading your ROMMON image to a stable release like is a critical maintenance task. It ensures hardware compatibility, patches security vulnerabilities, and prevents unexpected boot loops or system crashes during major IOS XE software transitions. Why Upgrade to ROMMON 17.3(1r)SG? (Exact command syntax can vary by ROMMON and
If the ROMMON variables are misconfigured, reset them to default factory settings using unset commands or use the sync command to save the current boot path variables.
: If using a specific slot instead of all , replace the keyword with your slot number. 3. Finalizing the Upgrade
Before upgrading, check your current ROMMON version:
ROMMON upgrade is . A failed upgrade (power loss during write, bad file, wrong hardware) leaves the RP in a non-bootable state.
Execute the upgrade command targeting your active Route Processor (typically slot R0 or R1).