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Compact Flash Error, 2811 - Won't Boot

A 2811 router recently was powered down and up, and on reboot, would only boot to ROMMON mode. We got this message during the boot cycle:

"Readonly ROMMON initialized

boot: cannot open "flash:"

boot: cannot determine first executable file name on device "flash:"

We read about the compact flash memory problem on some routers with certain flash modules. We have put the CF card in another 2800 series router, and the IOS image is readable there, but not on the original router.

After researching the problem on Cisco's website, we downloaded the ROMMON upgrade "C2800NM_RM2.srec.124-13r.T6", which we believed would fix this issue and also allow booting from a flash image on USB. We could then load an image into RAM from the USB and run the router, but still could not access flash. Should we have loaded the image "C2800NM_RM2.srec.124-13r.T5" first, before trying to load the "-.T6" version? Would that have fixed our compact flash problem? The CF card is still readable in other routers, so we know the flash card is okay.

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Boot the router with a recent image with tftp, command is tftpboot. You can skip copying this image to flash using "-b" IIRC.

Once router is up with IOS, upgrade rommon and try rebooting from flash again.

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In addition to Paolo's comment ...

1. After the tftpdnld of the IOS from the TFTP to the router, format the CF and/or USB using the router;


2. Maximum CF and/or USB size is 2Gb.

Why don't you go to the "C2800NM_RM2.srec.124-13r.T6" instead?


Leo, I did not recommended formatting the flash, because according to the OP, it works fine on other units.

So once the rommon is upgraded, the router should start recognizing it without problems.


An update from my side. The ROMMON has been upgraded with the C2800NM_RM2.srec.124-13r.T6, after one of our other techs did an xmodem to DRAM of the IOS image, and then did the ROMMON upgrade. However, the router still does not recognize the CF card, and while it now lists the CF card usbflash0 when I list devices, it still won't read either the USB or Flash. Any new thoughts? We could try to reformat the flash and or USB, but that will require another xmodem load of the IOS image, and that is likely to take some time.


First of all, you never need to suffer xmodem with an ISR router.

Download and install the free tftpd32.exe, in rommon type "tftpdnld". This will tell you which environment variables you have to set, of course pointing to the PC and image where you installed tftpd32.

As mentioned before, there is also a flag that let you boot without copying to flash, that is also very useful.

Now, I would like to see the console log of your rommon boot, and "show dev" or whatever equivalent rommon command is there that I can't remember now.

Or you can just go ahead, boot IOS and reformat flash as necessary.


If the CF can't be read, try the following:

1. In the router which can recognize the CF, copy the IOS from the CF to the USB flash;

2. Boot the 2nd router into ROMmon and, if memory serves me correct, enter the command "boot usbflash0:". (NOTE: USB is in USB port 0.)

Hope this helps.