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New Member

Switch to ROMMON from IOS


i'm not sure, but i think i heard once that it is possible to switch (not boot!) to ROMMON mode during a fully loaded/bootet IOS with some Key sequence.

Is that correct or am i mistaken? If so, to what platforms does that apply to? And where can i find literature about it?

Im running two 6509-E's with SUP-2T in VSS mode and i'd need to switch to ROMMON on the Standby core, without rebooting of course..



Everyone's tags (4)
Hall of Fame Super Silver

Switch to ROMMON from IOS

I've never seen any such feature if it exists.

On a VSS pair I'd think I'd have to do a "redundancy reload peer" from the active supervisor and be ready to break to boot process to get into rommon on the standby supervisor console when it it reloading.

More importantly, why would you want to do so?

Cisco Employee

Re: Switch to ROMMON from IOS

You cannot jump to rommon directly from IOS in any platform. You will have to reload a switch and stop it in rommon before it starts to boot into IOS. This could be done either by reloading a switch and do a Ctrl+C and stop it in Rommon. Or you could set the configuration-register to make it stop in rommon mode. The command from IOS is config-register ' x '.

Nagaraj R


Re: Switch to ROMMON from IOS

That may depend on the platform, but usually you need to change the config register to accept the break command. Afar this was 0x2002. With that value you could switch to rommon at any time with sending the break sequence. Of course the router ends normal operation and needs to be reloaded after that...

However I don't know how a dual sup setup behaves in such a sceanrio.



New Member

Switch to ROMMON from IOS

New Member

Switch to ROMMON from IOS

Thanks everyone for their replys.

As i said, i was not sure anymore if that feature really existed. So i guess the only option is a reload of the peer node.

Thanks for clarification.