From: Derek Small (dwsmall@xxxxxxxxxx)
Date: Tue Feb 20 2001 - 01:04:21 GMT-3
Scott,
The 2500 series (and earlier 1600 series) routers as called "run from flash"
routers. That is, they execute IOS instructions in flash memory, not RAM
like most conventional computing devices. Since you are executing code in
flash memory you cannot modify it, or you will, in effect, be modifying your
operational RAM, sometimes called an abend or general protection fault.
2500 routers give you the option of partitioning the flash memory into two
segments, so you can modify one, and leave the other undisturbed. To return
the router to a single partition you have to format the entire flash. To do
that, you have to boot the router to <boot> mode. 2500 routers do not have
boot flash, like some of the larger routers, but they do have a boot ROM
which holds a minimal IOS image, to get basic IP functionality working, just
like a boot flash image. Set the config register to 0x101 and reboot the
router to get it to boot to a router<boot> prompt. The flash memory will
then be writable. You can then format your entire flash as a single
partition and then tftp a new IOS to the router. Reset your config register
when you are done.
Derek Small
CCIE # 5832, CVoice, Nortel NCSE
dwsmall@fatkid.com
----- Original Message -----
From: "Scott Schneidewind" <schneids@ispchannel.com>
To: <ccielab@groupstudy.com>
Sent: Monday, February 19, 2001 4:18 PM
Subject: Changing flash from "Read only"
> Hello all.
> I have some 2501 routers which each have two 8Mb sticks of flash ram in
> them.
>
>
> "Show Flash" lets me know that one is read/write and the other is read
only.
> How can I change the read only partition...so it can be erased and
combined
> with the other one.
>
> -Scott
>
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