flash/nvram/startup config

[volleyman]

new to Cisco routers. can someone please explain the difference between the flash, nvram, and startup-config? I want to erase the config on a router so that I can configure it from scratch but I'm not sure what to erase what to leave alone. i don't want to wipe out the IOS!!!

 

[jimmyzz]

volleyman,

The flash memory is where you save and load your IOS from. You can also save backup copies of your running config to the flash memory. Do not erase the flash unless you intend on upgrading the IOS.

The nvram is where your startup-config is loaded from. There can only be one startup-config in nvram. If you want to configure the router from scratch, you need to erase the startup config.
> erase start

After you make your necessary config changes, copy the current (running config) settings as your new startup config.
> copy run start

JimmyZ

 

[volleyman]

so after I load the IOS into flash (I'm using xmodem), is there a command I need to run to save it? I tried it once and as soon as I power-cycled the router I was back to the Rommon 1 > prompt.

 

[lgarner]

There may be another problem. Once you load the IOS ("copy xmodem flash&quot you can type "show flash" and you should see the file. Assuming that it's there after you load it, watch the screen closely while booting to see if there are other error messages.

 

[volleyman]

I'm doing something very wrong and I'm getting frustrated!!

Immediately after the xmodem transfer completes, what command do I need to run in order to save the file? when the transfer finishes, I am at a working IOS prompt and my previous configuration is still there. I tried typing "save xmodem flash" but I get an I/O error.

If I reload or power-cycle, I automatically go back to the Rommon prompt. I noticed the following while booting:

loadprog: bad file magic number: 0x0
boot: cannot load "flash:"

what exactly does that mean and what should my next step be?

thanks!!!!!!!

 

[Syty]

Sounds like corrupted files to me, do you have another IOS or different flash RAM you can use for troubleshooting?

 

[volleyman]

I am trying a new download of the IOS right now from Cisco. I'll let you know how it goes.

 

[volleyman]

I tried a different version of IOS code, and I still have the same problem. I'm still getting the following error:

loadprog: bad file magic number: 0x0
boot: cannot load "flash:"


any ideas?

 

[Syty]

I would attempt to use different FLASH Memory at this point, it sounds bad.

I'll look up that error and ask around, maybe it's something specific....

 

[volleyman]

I believe the flash is working ok, because when I type in the following the router brings up the IOS with no problems:

> b flash: IOS

so it looks like the IOS is there along with my configuration, it just isn't bringing up the IOS when I boot the router. How do I point it to the correct flash location when it boots?

 

[hunkyprince]

U get the magic no.error when the config reg last value is zero and this automatically goes to romon mode when booted..i the problem is due to the corrupted files ..Some times bad memory can also lead to this mode