I have downgraded my Cisco 3640 IOS to a lower version. Now the router is unable to detect the 32MB flash that is installed.
The "show version" command does not display the flash memory (2 x 16MB). If I try to use "show flash:" an error message appeared pointing to the flash.
Funny thing is I am still able to use 'xmodem -c c3640...bin' to upgrade to a higher version IOS from the rommon mode.
Thanks for the help.