how to recover cisco router from rommon mode

The IOS image is decompressed, which can be seen as a string of hashtags (#), and loaded into DRAM. When you power up a Cisco router or switch, it first begins the power-on self-test (POST) to ensure that the device functions properly, and then it looks for the IOS from flash memory. Flash memory provides non-volatile storage, which means that the content of the memory is not lost when the device loses power or reloads. bin file (it can also be stored on a TFTP server).

In this article, I will describe the problem of a router stuck in ROMmon mode, together with my recent experience.įor those of you that are not familiar with the term ROMmon (ROM monitor) mode, it is a bootstrap program that initializes the hardware and boots the Cisco IOS software when you power on or reload a router or switch.Īlso, Cisco Internetwork Operating System (IOS) is the system software in Cisco devices, and is usually (and by default) stored in a memory area called flash as a. or you experienced a physical layer problem, like I did.you ”accidentally” entered a break key sequence to the console of your router, found yourself in ROMmon mode and do not know how to get out of it.

you did not upgrade the amount of DRAM before upgrading the IOS.an IOS on a router has been (accidentally) deleted from flash.router was unable to find the IOS (either on Flash or TFTP server).corrupt image (IOS) on Flash (indicated by bad_checksum message).configuration register forced the router to go to ROMmon mode during the boot process.

If you have ever experienced the ROMmon mode problem, you probably came across one of the following:

How to recover cisco router from rommon mode