Cisco Support Community
Showing results for 
Search instead for 
Did you mean: 

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. And see here for current known issues.

New Member

How to upgrade the rommon in Catalyst 4500X VSS

Hi to all,

how to upgrade the rommon on a VSS with 4500X ?

- copy the rommon software to bootflash and sup-bootflash.

- reload and type ctrl-c for break sequence

- Configure the boot parameter in rommon mode .

   boot cat4500-e-promupgrade-150_1r_SG2

Is this the way it works ? Or is this only for redundant supervisor engines in one chassis

Thanks in advance



Cisco Employee

How to upgrade the rommon in Catalyst 4500X VSS

New Member

How to upgrade the rommon in Catalyst 4500X VSS

Hi Inayath

thanks for the link, but for my understanding is this for switches in standalone mode or with redundant sups

But I am looking for a VSS upgrade.

Regards Alex



today I had the same question and found this unanswered discussion.

So here's what I did, it may help others:


#conf t
(config)#no boot system
(config)#boot system bootflash:cat4500-e-ios-promupgrade-150-1r-SG10
(config)#boot system bootflash:cat4500e-universalk9.SPA.03.06.02.E.152-2.E2.bin

#show bootvar
BOOT variable = bootflash:cat4500-e-ios-promupgrade-150-1r-SG10,12;bootflash:cat4500e-universalk9.SPA.03.06.02.E.152-2.E2.bin,12;
CONFIG_FILE variable does not exist
BOOTLDR variable does not exist
Configuration register is 0x2102

Standby BOOT variable = bootflash:cat4500-e-ios-promupgrade-150-1r-SG10,12;bootflash:cat4500e-universalk9.SPA.03.06.02.E.152-2.E2.bin,12;
Standby CONFIG_FILE variable does not exist
Standby BOOTLDR variable does not exist
Standby Configuration register is 0x2102

#redundancy reload peer

! when the peer is online again
#redundancy force-switchover
#This will reload the active unit and force switchover to standby[confirm]

! when the entire system is up again
#conf t
(config)#no boot system bootflash:cat4500-e-ios-promupgrade-150-1r-SG10


Basically what you'd do for a 'normal' IOS-update, just with an additional entry for the promupgrade first in the boot loader.




Hall of Fame Super Gold

Rolf,  Don't forget to remove



Don't forget to remove the first boot variable string instructing to load the ROMmon after the process has been completed. 

Thanks Leo, a valid point!I

Thanks Leo, a valid point!

I wanted to keep this how-to sequence compact, but some additonal lines won't hurt :)

CreatePlease login to create content