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eric10276
Beginner

Catalyst 2960S Format Flash Failure

I recently tried to manually format the flash on a model WS-2960S-48TS-L switch running IOS version 15.0(2)SE.  While executing the operation I got the following error - mifs[8]: Failed to create superblock  %Error formatting flash (I/O error).

As a result the flash is no longer accessible by the switch.  I spoke with Cisco and they indicated that a switch reload would remount the flash and make it accessable again but the .bin file would need to be reloaded using the xModem recovery procedure (what a pain).

The next IOS version 15.0(2)SE1 will supposedly fix this bug but it has not been released yet.  In the meantime if you are running 15.0(2)SE you may want to hold off performing a "format flash:" function on a 2960S.

3 REPLIES 3
Leo Laohoo
VIP Community Legend

I spoke with Cisco and they indicated that a switch reload would remount the flash and make it accessable again but the .bin file would need to be reloaded using the xModem recovery procedure (what a pain).

xModem on a 2960S????  Ahhhh ... OLD SCHOOL.  2960S has a USB port.  Care to guess what you can use that for?

I have successfully pat down the proceedure to boot a 2960S (from ROMmon) via USB.  Heck, the same proceedure works for all ISR G1 (except 870), ISR G2 and switches like 3560E/X and 3750E/X.

It's not rocket-science.  Here's how it goes:

1.  NOT ALL USB sticks are compatible/supported;

2.  I have tested up to 4 Gb and it works;

3.  Format the USB to FAT16;

4.  Copy the BIN file across;

5.  To boot from ROMmon, use the command "boot usbflash0:IOS.BIN".

The next IOS version 15.0(2)SE1 will supposedly fix this bug but it has not been released yet.  In the meantime if you are running 15.0(2)SE you may want to hold off performing a "format flash:" function on a 2960S.

I am using 15.0(2)SE on my 2960S and I've used the "format flash:" command and it works.  I disagree with what Cisco says that it's a bug.  From ROMmon, you may want to issue a "chkdsk" to ensure the flash is not faulty.

Thanks for the input.  I have used the USB port for configuration but never thought to use it for a recovery.  Also I will try the "chkdsk" as I am not convinced Cisco's guidance is accurate in this case.

Update - I reloaded the 2960S switch and the flash memory did remount as Cisco predicted.  All files in flash were gone but I successfully loaded the latest IOS release 15.0(2)SE1.  After recovering the switch I am now able to format the flash memory with no issues.  If you look at the release notes for IOS version 15.0(2)SE1 it does list the flash memory format issue as a bug fix. 

I don't know which models of the 2960S are affected by this bug but again if you are running 15.0(2)SE you may want to avoid formatting the flash manually until you migrate to 15.0(2)SE1.