Update your Cisco rom to the latest version. Howto update rom
In this post I have used the Cisco 1841 router.
Cisco 1841 IOS images can be downloaded here. Be sure the size of de flash and
the amount of DRAM is equal to the Cisco Router.
1. Insert the USB drive (FAT Formatted) into your computer and copy the image from your computer to the root of the USB drive.
3. Connect to the device from a terminal and go into the user privileged mode.
4. Make a backup of your old IOS image.
Router#copy flash:c1841-adventerprisek9-mz.124-24.T6.bin usbflash0:
Destination filename [c1841-adventerprisek9-mz.124-24.T6.bin]?
Copy in progress...CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC
40523476 bytes copied in 72.732 secs (557162 bytes/sec)
5. Replace the old IOS image with the New IOS image.
Router#copy usbflash0:c1841-advipservicesk9-mz.151-4.M6.bin flash
Destination filename [c1841-advipservicesk9-mz.151-4.M6.bin]?
Copy in progress...CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC
45723632 bytes copied in 153.444 secs (297983 bytes/sec)
6. Type “yes” when asked if you want to overwrite the current IOS. Else delete the old IOS image with the delete commando.
7. Type “reload” to switch from the old IOS to the new one.
In some cases it’s better to change the bootvar (show bootvar)
#1 Go into the configure mode.
#2 no boot system
#3 boot system flash::c1841-advipservicesk9-mz.151-4.M6.bin