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Cisco register: boostrap code


I have found a lots of documentation on the bootstrap but there is still one thing unclear to me. What is the difference between being into a boostrrap mode and ROMMon. Do we have a different set of command between these two modes. Why would we want to boot in a bootstrap mode.

Does newer platform like 2800 or 3800 support bootstrap mode.

Thanks for your help

Cisco Employee

Re: Cisco register: boostrap code

Hello Stephane,

My understanding is that the ROMMON is the basic code stored in the ROM and serves as the bootloader and disaster recovery environment. It would be somewhat similar to a BIOS or CMOS setup software stored in FLASH memory in normal PCs.

The boostrap is actually an IOS that is limited in its networking capabilities and its primary purpose is loading a full IOS image that cannot be for whatever reasons loaded directly by the ROMMON. For example, the full IOS may reside on a storage medium that is not directly supported by the ROMMON but that is accessible by the boostrap IOS. On modular switches, it may be necessary to boot different line and feature cards with special precautions - a task again more suited for a bootstrap IOS than for a limited ROMMON.

I have never had an opportunity to really work with helper images but I remember seeing some of them in the download section of the Cisco website for some high-end switches/routers.

Best regards,



Re: Cisco register: boostrap code

The 'boot image' or 'bootloader' is the limited IOS which can land you into 'boot' prompt if the main IOS fails to load. This bootloader is availble only on certain platforms like the 7200. The 'boot', 'mboot' and 'kboot' are the three available types of boot images on the 7200

As far as I know, the bootstrap is same as the ROMMON

Bootstrap/ROMMon upgrades are available in certain platforms, while some platforms automatically upgrade the bootstrap when you upgrade IOS

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