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Booting Router with IOS in USBFLASH:


I m using a 2800 router. I need to boot with an ios thats in the usbflash: i have loaded the usb with the necessary ios with fat file system. and on rommon mode i gave

"boot usbflash0:c2800nm-ipbase-mz.124-3i.bin" command and i got error *** TLB (Load/Fetch) Exception ***

Access address = 0x364

PC = 0x8003d878, Cause = 0x8, Status Reg = 0x3040a803

I have tried with boot system command on roommon but getting the error message. I have upgraded the boot rom

Please advice me on what to do?


Hall of Fame Super Silver

Re: Booting Router with IOS in USBFLASH:

Hello Lakshmy,

here is a link to QA about USB flash support

However, you can try to insert boot commands in IOS in order to have it load the image in flash.

boot system boot usbflash0:c2800nm-ipbase-mz.124-3i.bin

verify that this is the first boot command in sh run

with sh run | inc boot system

if so just do wr mem


remove the command that is before the one you added and then reissue it

you do again sh run | inc boot system

if this time the usbflash0: is in first row. ok do wr mem

do sh ver

verify that config register is 0x2102 or 0x0102.


this requires to have a valid IOS in bootflash or in a compact flash.

Hope to help


Super Bronze

Re: Booting Router with IOS in USBFLASH:

Are you using a Cisco USB flash or brand "x"?

If the latter, not all work. Also it seems important, besides formatting with FAT, to use 256 MB or smaller (which are a bit hard to buy new anymore, i.e. those that small).

It's also important to have the newer boot rom update, but I see you say you've already done that, but do insure you're router is using it (IOS show version will confirm).

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