Introduction
The rommon is needed for maintenance purposes, such as password recovery, TFTP downloads in cases where the flash file is corrupt or you dont have access to regular router mode. Can also be used for doing diagnostic tests. The tftpdnld ROM Monitor (ROMmon) recovery procedure must be done in a specific way in order to work properly. Inputting the commands with incorrect syntax or variables causes the procedure to fail. If the tftpdnld ROMmon command recovery procedure fails, verify that the following conditions are met:. The TFTP server is running. Number of times the router attempts ARP and TFTP download. The default is 7. Rommon 1 confreg 0x2101. Note If you are using a PC to download a Cisco IOS. Booting a Cisco IOS Router from a USB Flash Drive in Rommon Mode. Cisco routers typically store a copy of the device’s operating system (Cisco IOS) in their flash memory, and load this operating system image into RAM during the boot-up process. Download Cisco Commands Cheat Sheets. Enter your Email below to Download our Free Cisco.
Rommon #7 set. The availability of the TFTP server is checked with the “ping server” command: rommon #8 ping server. Once you’ve ensured that the workstation with TFTP server software and Cisco ASA firewall are connected and configured correctly, enter the command “tftp” to start the process of loading the IOS: rommon #8 tftp.
This document explains how to download a software image to a Cisco 2600/2800/3800 Series Router using Trivial File Transfer Protocol (TFTP) over the first LAN port using the ROMmon tftpdnld command.
Rommon 9 dir flash: File size Checksum File name 3686656 bytes (0x384100) 0x1a5e c1600-sy-mz.121-16.bin; Change the config register back to 0x2102 and reset or power cycle the router so that the new Cisco IOS software image gets loaded. Rommon 10 confreg 0x2102 You must reset or power cycle. The tftpdnld ROM Monitor (ROMmon) recovery procedure must be done in a specific way in order to work properly. Inputting the commands with incorrect syntax or variables causes the procedure to fail. If the tftpdnld ROMmon command recovery procedure fails, verify that the following conditions are met:. The TFTP server is running.
Notes:
The ROMmon TFTP transfer works on the first LAN port only. However, for the Cisco 2612, you can choose the Token Ring or Fast Ethernet port.
You can only download files to the router. You cannot use ROMmon TFTP to get files from the router.
The transfer does not support route bridging on Token Ring ports.
Prerequisites
Requirements
There are no specific requirements for this document.
Components Used
This document is not restricted to specific software and hardware versions.
Conventions
Refer to Cisco Technical Tips Conventions for more information on document conventions.
Cisco Asa Rommon
Operation
First, you must set ROMmon environment variables prior to the TFTP download. All variable names are case sensitive.
Cisco Boot From Rommon
You can view the ROMmon environment variables by using the set command, as shown here:
The variables to set for tftpdnld are shown here:
Cisco Tftp Download From Rommon Mac
Note: As detailed in Cisco bug ID CSCdk81077 (registered customers only) , for Cisco 2600 and 1720 Series Routers running the ROM monitor command tftpdnld, the command might report a bad checksum comparison when it loads Cisco IOS software images of Cisco IOS Software Release 12.0(2.2)T or later.
Cisco Rommon Show Flash
Note: As a workaround to this problem, set the ROM monitor variable TFTP_CHECKSUM to 0. This is done by defining the variable TFTP_CHECKSUM=0 from the ROM monitor setcommand, and then proceeding with the tftpdnld procedure.