3850 booting up rommon mode

Hi All,
While booting up a new 3850 after copying image on to flash i am getting error
and it stops at switch: prompt

The system is unable to boot automatically. The
BOOT environment variable needs to be set to a
bootable image.

How to solve this?

Hello Abhishek

It seems that for some reason the device is unable to read the IOS. This could mean that the IOS image is corrupted, is non existent, or the boot variable doesn’t point to it.

First, make sure the file has successfully been transferred. Secondly, make sure the file is not corrupt. Use the MD5 file validation feature to confirm the integrity of the file. Look at this Cisco documentation to see how to do that. If it is corrupt, try reloading the image.

If the image is fine, take a look at the boot variable. Make sure that the boot system command points to the right image file. You can use this command to specify the specific IOS image file to load. More info on this can be found here.

I hope this has been helpful!


Hi Liz ,
the problem i see is very uniquq.

Is it not correct that At any point of time boot variable if we already have the boot variable should be pointing to packages.conf but in my case it always shows something like packages.conf 00 (under show version)
i tried many things but no luck…any idea how can we change it to packages.conf ?


Hello again Abhishek

Since the boot variable is pointing to something like packages.conf 00, then this means that it is actually pointing to a rollback software package. This means that when you did a new install, the router saved the old software in a packages.conf 00 file that allows you to roll back the installation. The 00 indicates how many installs ago this rollback goes back to.

This might actually be a good thing because you may be able to automatically roll back to your original IOS installation that was functioning correctly. Take a look at this Cisco link, near the bottom, where some of the rollback instructions can be found.

Try it out and let us know.

I hope this has been helpful!