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new 2851 can't boot up

Hi, we just have a new 2851 router come in and I powered it up. howerver after initialing the memory checking, it goes not go any anywhere? any idea ? it's brand new, just out of box. thanks

Cisco Employee

Re: new 2851 can't boot up


Can you try ejecting its Compact Flash card and turning it on? With the CF card removed, the router should be able to boot into the ROMMON mode. If it does not then I am afraid it is ready for replacement.

If it does boot into the ROMMON then most probably the CF card contents are corrupted. In that case, I would suggest using the tftpdnld command to download and boot the IOS from a TFTP server and subsequently reformat the CF and put the IOS back. You would need a TFTP server with an appropriate IOS image.

This document describes the process of using the tftpdnld command:

However, I suggest not storing the IOS image into the CF card directly using the tftpdnld command, rather I suggest downloading it directly to RAM by the "tfpdnld -r" command and only after it boots up, you should format the CF using the "format flash:" command and store the IOS image from the TFTP server to the CF card by the means of the usual copy command. The reason for this is that there are two possible filesystems for a CF card. The ROMMON creates the legacy filesystem which is being deprecated. The "format" command creates a FAT filesystem which is the preferred option.

Best regards,


Hall of Fame Super Silver

Re: new 2851 can't boot up


Peter has good suggestions here. But before you do his suggestions I would suggest that you simply remove and reseat the compact flash. I have had expereinces with these routers where the CF appears to be right but is really not quite fully seated.

If reseating the CF does not revolve the issue then you should follow the suggestions from Peter.



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