Cisco 2811 512MB CF card readable by IOS but not by rommon

[Will Hrudey]

Hello,

I have two MS-DOS (FAT 16) 512MB Compact Flash cards (Cisco brand) and I can't seem to get my either of my two 2811 routers to read these cards in rommon. 

I can read them on my PC and I have confirmed FAT 16 formatting.   When I boot the router, rommon reports

open(): Open Error = -66

boot: cannot open "flash:"

boot: cannot determine first executible file name on device "flash:".  

If I load an image from tftp using tftpdnld -r, it loads a 15.1 image successfully into memory and I have subsequently formatted the CF card (format flash: ) from IOS successfully.  show flash: works fine.  I have even copied another image over to the 512MB flash via my IOS session using tftp.   IOS doesn't have any issues with the CF card.   I can do a "show flash: all" and it reports multiple partitions. However, when reload the router, the boot stage dumps execution control into rommon indicating that it can't read the CF card ... error -66 again.  

I have looked at Cisco's Using Compfact Flash Memory cards whitepaper and read some other posts where the poster indicated the CF card lost its partitions.  However, in my case, i have reformatted using "format flash:" which should create a class C filesystem.  

I have also seen various posts that indicate the 2811 can support up to 2GB flash sizes so this 512MB card should be fine. 

Any ideas?  this seems more complicated that it should be.

Thanks in advance...

Will

[K S]

I know this is an old post but maybe the info will still help.

When you format the CF card on windows (8.1), change the allocation unit size to 64 kilobytes.  I ran into the same issue using a 512mb Cisco branded card. My default allocation unit size was 8192 bytes in which the router was unable to recognize the CF card.

[Leo Laohoo]

Unless you know what you are doing, I never recommend anyone format a CF using a PC/laptop.  I will always recommend you format using the router.  Why?  Because if the CF is supported, you can format the CF. 

[K S]

Not always true, as I just ran into this issue with a 2811 not seeing/formating a card that Windows could read.  Changed the allocation size to 16kb and the router could see and format although windows couldn't read the CF card afterwards. Changed it to 64kb and everything was golden on both devices. 

I say experiment and you will 9 times out of 10 learn something out of it. It's no surprise that transferring IOS images via copy/paste is much less of a hassle then TFTP when accessibility is available. 

[Lukas Kuzmiak]

got the exact same issue on 2821, 1GB original Cisco card from Amazon. IOS would recognize it, rommon would not.

I tried re-partitioning, re-formatting and erasing on the very same router in IOS (booted from a a different card). It would always lead to 16kb allocation size which rommon did not recognize (exactly same error as original poster mentioned).

Formatting with 64kb allocation size made rommon recognize the card (perhaps number of sectors and sectors per cluster decreased or i have no idea why .. 

But nothing else I found anywhere worked for rommon to recognize it. IOS has no issue on the same router all the way through this nightmare.

Thanks KS!

[Joseph W. Doherty]

I recall there were ROMMOM upgrades for some of the 28xx series.  It's possible you'll obtain different behaviors depending on the ROMMOM version.

[Lukas Kuzmiak]

I tried upgrading the ROMMON before I got into all of this juggling around (I thought it must be that considering IOS sees the card and ROMMON doesn't).

I upgraded to:

ROMMON: System Bootstrap, Version 12.4(13r)T11, RELEASE SOFTWARE (fc1)

Which AFAIK is the latest version for 2821 - result was however exactly the same, that's why I got into the weird tweaking of FAT filesystem parameters as I didn't see what else I could do.

[Leo Laohoo]

12.4(13r)T11 is the last and final ROMmon version.  There is a hidden command to boot the IOS from a USB stick (in ROMmon):  boot usbflash0:IOS_filename.bin

[Leo Laohoo]

I agree with Joseph.  Upgrade the ROMmon and see if there are any improvements.  Another added benefit with a ROMmon upgrade (the latest one) is the ability to boot the IOS, from ROMmon, using a supported USB thumb/flash drive.

[Star2BarryN]

I had a similar issue with a 256 MB flash card. When I started experimenting, I noticed all my bootable flash cards had a disk geometry that had 32 sectors per track and the first partition had an offset of 32 sectors while the one that refused to boot had 63 sectors per track and the offset to the first partition was 63 sectors. I used the fdisk command line program on my Macintosh and used the "disk" command to change the CF card disk geometry from 993 cylinders 8 heads 63 sectors per track to 978 cylinders 16 heads 32 sectors per track and then repartitioned the card and made the offset to the first partition 32 sectors. I set the partition as type 6, marked it as active, and formatted it with FAT16. After doing this and coping the IOS file to the CF card, the IOS loaded from Rommon without issue. Here is part of the output of "show flash:" for the working format:

ATA CARD GEOMETRY
   Manufacturer Name     
   Model Number           TOSHIBA THNCF256MDG
   Serial Number          TSBC256M06914T88181A
   Firmware Revision      3.00   
   Number of Heads        16   
   Number of Cylinders    978  
   Sectors per Cylinder   32   
   Sector Size            512  
   Total Sectors          500736

ATA PARTITION 1 INFO
   Start Sector           32   
   Number of Sectors      500704
   Size in Bytes          256360448
   File System Type       FAT16
   Number of FAT Sectors  245  
   Sectors Per Cluster    8    
   Number of Clusters     62522
   Number of Data Sectors 500176
   Base FAT Sector        1    
   Base Root Sector       491  
   Base Data Sector       523 

[#11]

Have same problem od Cisco 6500. Rommon does not recogizes CF formated in IOS (says Invalid Magic Number).

Problem was missing "monlib" at CF:

#show disk0: filesys
ATA MONLIB INFO
   Image Monlib size      61228
   Disk Monlib Size       NA
   Disk Space Available   NA
   Name                   NA
   End Sector             NA
   Start sector           NA
   Updated By             NA
   Version                NA
   Monlib Version         1426085376
   Monlib Params Version  1459640320

Before formating in IOS you need recreate partition what also writes "monlib":

#partition disk0: 1
#format disk0:
#show disk0: filesys
ATA MONLIB INFO
   Image Monlib size      61228
   Disk Monlib Size       61228
   Disk Space Available   65024
   Name                   c7200-atafslib-m
   Start sector           2
   End sector             121
   Updated By             s72033_sp-ADVIPSERVICESK9-M15.3(3)S5
   Version                1

After that, rommon recognizes disk and if you copy IOS there, will boot from it.

My CF was not Cisco branded - it was normal Apacer CF card.

Maybe this helps somebody.