Excuting "show flash:" causes error (flash not display during show version)

[pllim]

After downgrading my 3640 router IOS, I have a problem where the flash is not shown when I execute "show version" or "show flash".

Here's what I got when I execute "show flash:" -

#show flash:

^

% Invalid input detected at '^' marker.

Everytime when I reload the router, the message below appears during boot-up -

% Crashinfo may not be recovered at flash:crashinfo

% This file system device reports an error

In ROMMON mode, I can run the command below -

rommon 6 > dir flash:

get_man_dev: Unknown device - probably NOT formatted.

get_man_dev: Unknown device - probably NOT formatted.

File size Checksum File name

22893664 bytes (0x15d5460) 0x9df1 c3640-is-mz.123-11.T10.bin

rommon 7 >

Thanks in advance.

[deepak.pandey]

It seems that filesystem on flash is got currupted

Issue the following commands for recovery

rommon>format flash:

rommon>IP_ADDRESS=xxx.xxx.xxx.xxx

rommon>IP_SUBNET_MASK=xxx.xxx.xxx.xxx

rommon>DEFAULT_GATEWAY=xxx.xxx.xxx.xxx

rommon>TFTP_SERVER=xxx.xxx.xxx.xxx

rommon>TFTP_FILE=

rommon>tftpdnld

[pllim]

How do I get to the 'rommon>' mode?

Is it the same as pressing the Break key when the router is powering up? If I do this, I will get to the 'rommon #>' mode ('#' is a number). From here, when I type the command 'format', I get a response showing the command not found.

[pllim]

I have not tried in rommon mode, but whenever I used the 'flash:' word in normal mode, it always say 'invalid input detected..'.

It seems the router doesn't know the flash exists.