topic boot system change from rommon in Network Security

boot system change from rommon

manuadoor — Mon, 11 Mar 2019 20:36:27 GMT

Dear Team,

I have multiple os stored in my flash, as my upgraded os is crashed I want fall back to old os stored in flash, Is this possiblie to change the boot system from rommon. if possible what are the steps

Thanks

Manu B.

Re: boot system change from rommon

varrao — Sat, 21 May 2011 07:20:26 GMT

Hi Manu,

Here is s adoc for it, you can use it to booot image from rommon:

http://www.cisco.com/en/US/customer/docs/security/asa/asa80/configuration/guide/trouble.html#wpxref83416

By the way is the device not booting up, if it is booting up then u can use the following commands to change the boot parameters:

boot system flash:/

wr mem

reload

this would boot the ASA with the OS that yuo want.

Hope this helps.

Thanks,

Varun

Re: boot system change from rommon

manuadoor — Sat, 21 May 2011 10:35:24 GMT

unfortubately the link is forbidden..

Device is not booting up, can I edit the boot system in rommon?

Re: boot system change from rommon

varrao — Sat, 21 May 2011 10:40:46 GMT

Hi Manu,

You cannot change the boot parameters but you can definitely upload a new image from tftp in rommon mode.

here I am attaching the document for you.

thanks,

Varun

Thats not correct. You can

ndemers — Thu, 18 Jun 2015 23:44:19 GMT

Thats not correct. You can choose which image to boot from rommon. You just have to look a little bit.

Look for a Valid Image in Flash:

If the configuration register value is set to make the system boot automatically from a default Cisco IOS software image, and if no break signal is sent during start up, the router should boot normally. However, if the router still enters the rommon mode, it is most likely because the router is unable to locate a valid Cisco IOS software image.

In this case, the first thing you need to do is look for a valid Cisco IOS software image in each available device. Issue the devcommand to see which devices are available on your router:

rommon 1 > dev 
     Devices in device table:
             id  name 
     bootflash:  boot flash
         slot0:  PCMCIA slot 0 
         slot1:  PCMCIA slot 1
        eprom:  EPROM 
     rommon 2 >

Next, issue the dir [device ID] command for each of the available devices, and look for a valid Cisco IOS software image (the device ID is slot0: and/or slot1:, corresponding to the PCMCIA cards inserted in the respective slots):

rommon 2 > dir slot0:
         File size           Checksum   File name
  12566060 bytes (0xbfbe2c)   0x38d1c81b    c7200-ik8s-mz.122-10b.bin
rommon 3 >

Note that if the router returns a "bad device name" message, the device specified probably does not exist.

The output of the dir slot0: command above indicates that a valid image is indeed present in the Flash. Try to boot from that image by using the boot command.

rommon 3> boot slot0:c7200-ik8s-mz.122-10b.bin
CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC
CCCCCCCCCCCCCCCCCC

http://www.cisco.com/c/en/us/support/docs/routers/7500-series-routers/15082-recovery-c7500.html#look_for_valid