[c-nsp] Sup720 image

[Reuben Farrelly]

On 21/08/2006 1:31 a.m., Saku Ytti wrote:
> On (2006-08-20 12:00 +0100), Will Hargrave wrote:
>  
>> If you have a unix box (there may be a windows app to do it I suppose) 
>> and a CF card you can just get a disk image from someone and dd it onto 
>> the CF. No physical media transfer required.
> 
> I really doubt this works, even if you format lets say cflash in VXR or
> GSR (or possibly 7600 with 'wrong' IOS), copy 7600 IOS there and insert
> the cflash on running 7600, you will happily see IOS there and you can
> verify md5sum to be correct, however you can not boot from there, as rommon
> does not see anything there, unless it's formatted in 7600 with correct
> IOS.

Yup.  It seems that formatting those cards in a switch/router adds/configures a 
special invisible area called a Monlib at the start of the card, as seen here:

router#show flash: filesys
******** ATA Flash Card Geometry/Format Info ********

.. <snipped> ...

ATA MONLIB INFO
    Image Monlib size = 52248
    Disk monlib size = 56832
    Name = piptom-atafslib-m
    Monlib Start sector = 2
    Monlib End sector = 104
    Monlib updated by = C1841-ADVSECURITYK9-M12.4(4)T2
    Monlib version = 1

router#

Without that Monlib area configured, you cannot boot from the card.  Been there 
tried that before...

In the case above the Monlib file was created while running an 1841 image, so it 
will likely only boot from an 1841 router, although other platforms will be able 
to read the card they won't be able to boot from it.

So yes, you can put them in any old CF card reader and copy/move files to and 
from the card, but you must format it in the router/switch FIRST to set up the 
magic boot area.

reuben