Recover a Router from Corrupted or Missing Software Image

Transcription

1 Cisco SMB Support Assistant Recover a Router from Corrupted or Missing Software Image Cisco Profile Contacts & Feedback Help Home > Work With My Routers > Cisco Routers > Recover a Router from Corrupted or Missing Software Image Service Requests Recover a Router from Corrupted or Missing Software Image Introduction Requirements Obtain the Software Image File Connect the PC to the Router Recover the Router from ROMmon mode Check Configuration Register Settings Look for a Valid Image in Flash Load the new software image with the TFTP server Next Step Troubleshoot the Procedure Related Information Download PDF Recover a Router from Corrupted or Missing Software Image Open a service request Update a service request Feedback Please rate this site: / Suggestions for improvement: Introduction This document explains on how to recover your Cisco Router from corrupt or missing software image. This procedure applies to the 800, 1700, 1800, 2600, 2800 and 3800 models of Cisco routers. If Cisco may contact you for more details or for future feedback opportunities, please enter your contact information: Full Name: Requirements To perform the steps described in this document, you need to have these items: Physical access to the Router that is installed and powered on A Windows PC with terminal-emulation software, such as HyperTerminal. A cross-over cable and a console cable. Refer to Cable Descriptions for further information. A new Cisco IOS software image provided to you by the SMB Technical Assistance Center (SMB TAC). (1 of 10)11/30/ :21:09 PM

2 Obtain the Software Image File Follow these steps to obtain a new software image: 1. If your Router software image is corrupted or missing, contact the SMB TAC to obtain the required software image. 2. Once you receive the software, take note of the exact name of the image file. The file has a similar name to this example: c2600-i-mz bin 3. Place the software image file in your C:\TFTP-Root directory. Connect the PC to the Router Complete these steps to connect the PC to the Router: 1. Connect your RJ-45 Ethernet port of your PC to the first LAN port or FastEthernet port or Gigabit Ethernet port of the router with a cross-over Ethernet cable. 2. Configure your PC with the IP address and with a subnet mask of For detailed instructions, refer to Configure an IP Address on Your PC. 3. Save the router software image in your C:\TFTP-Root directory. If you do not have a new image, contact the SMB Technical Assistance Center (SMB TAC) for assistance. 4. Launch your TFTP server program. 5. Connect your PC to the router with a console cable. You need a console access to your router in order to boot the router with a new software image. Note: Create a HyperTerminal connection to your router. For more information, refer to Create a HyperTerminal Connection. (2 of 10)11/30/ :21:09 PM

3 Recover the Router from ROMmon mode Follow these steps to recover the Router from the ROMmon mode: Check Configuration Register Settings Use this procedure to recover the router from the ROMmon mode, before you try to upgrade the router software image with the TFTP server. You can use this, only if your flash has a valid IOS software image. 1. If the router is stuck in ROMmon mode each time the router is restarted, it is probably due to the setting of the configuration register. Type confreg at the ROMmon prompt to verify the configured value of the configuration register. You can see the similar output: rommon 1 >confreg Configuration Summary (Virtual Configuration Register: 0x2100) enabled are: load rom after netboot fails console baud: 9600 boot: the ROM Monitor do you wish to change the configuration? y/n [n]: 2. In the output of the confreg command, the configuration register is set to a value 0x2100 that forces the router to go into the ROMmon mode each time it is reloaded or power-cycled. To make the router boot automatically from a default Cisco IOS software image, change the configuration register to a value 0x2102 as indicated in step Type confreg at the ROMmon prompt. Enter y in response to the question do you wish to change the configuration in the output. rommon 2 >confreg Configuration Summary enabled are: load rom after netboot fails console baud: 9600 boot: the ROM Monitor do you wish to change the configuration? y/n [n]:y 4. Enter n to all questions except to the question change the boot characteristics? y/n [n]:. Enter y to change the boot characteristics? y/n [n]: y and enter digit 2 in enter to boot: enable "diagnostic mode"? y/n [n]:n enable "use net in IP bcast address"? y/n [n]:n disable "load rom after netboot fails"? y/n [n]:n enable "use all zero broadcast"? y/n [n]:n enable "break/abort has effect"? y/n [n]:n enable "ignore system config info"? y/n [n]:n change console baud rate? y/n [n]:n change the boot characteristics? y/n [n]:y enter to boot: (3 of 10)11/30/ :21:09 PM

4 0 = ROM Monitor 1 = the boot helper image 2-15 = boot system [0]:2 Configuration Summary (Virtual Configuration Register: 0x2102) enabled are: load rom after netboot fails console baud: 9600 boot: image specified by the boot system commands or default to: cisco2-c3825 do you wish to change the configuration? y/n [n]: n You must reset or power cycle for new config to take effect Note: You have changed the configuration register to a value that makes the router to look for a valid Cisco IOS software image on startup and boot from the same. Reset the router now. 5. Type reset at the ROMmon prompt. rommon 3 >reset System Bootstrap, Version 12.3(11r)T1, RELEASE SOFTWARE (fc1) Technical Support: Copyright (c) 2004 by cisco Systems, Inc. Total memory size = 256 MB - DIMM0 = 256 MB, DIMM1 = 0 MB c3825 processor with Kbytes of main memory Main memory is configured to 72/0(dimm 0/1) bit mode with ECC enabled Upgrade ROMMON initialized program load complete, entry point: 0x , size: 0x22f97a8 Self decompressing the image : ################################################# ########################################################################## [OK] ----Output truncated The router must now reload with the new Cisco IOS software image. If the router still goes to ROMmon mode proceed to the section Look for a Valid Image in Flash. Look for a Valid Image in Flash If the configuration register value is set to make the system boot automatically from a default Cisco IOS software image, the router must boot normally. However, if the router still enters the ROMmon mode, it is probably because the device is unable to locate a valid Cisco IOS software image. Follow these steps to look for a valid Cisco IOS software image. 1. Type dev at the ROMmon prompt to display the file system that you use such as a flash or slot or disc. (4 of 10)11/30/ :21:09 PM

5 rommon 1 >dev Devices in device table: id name flash: compact flash bootflash: boot flash eprom: eprom rommon 2 > 2. Identify the router file system and type dir <file-system> which lists the files and directories in the file system. The keyword filesystem is either a flash or slot or disc. For example if you use flash file system type dir flash: at the ROMmon prompt to look for a valid image. rommon 2 >dir flash: Directory of flash: rw- c3825-advipservicesk9-mz bin rw- sdmconfig-38xx.cfg rw- sdm.tar rw- es.tar rw- common.tar rw- home.shtml rw- home.tar rw- 256MB.sdf 0 0 -rw- config_log_persist_dbase rw- vlan.dat 3. The output indicates that a valid image c3825-advipservicesk9-mz bin is indeed present in the Flash. Try to boot from that image with the boot command as specified in step If the router returns the dir: cannot open device flash: or bad device name" message, the device specified probably does not exist. If you have a 2800 or 3800 ISR, try to reset the flash card on the router or replace with the new one installed with IOS image. After that, reload the router. If it goes to ROMmon again, go to step Type " boot flash:[directory] [filename] " which boots the router. For example "boot flash:<image-name>" or boot slot<0/1>: <image-name> or boot disco<0/1>:<image name>, depends on the file system you use. rommon 2 >boot flash: c3825-advipservicesk9-mz bin program load complete, entry point: 0x , size: 0x22f97a8 Self decompressing the image : ################################################# ################################################################################ ########################################################################## [OK] ----output truncated (5 of 10)11/30/ :21:09 PM

6 Note: The router must now boot with the Cisco IOS software image specified in the boot command. 6. However, there are times when a valid image does not exist on any of the devices or the image on the Flash is corrupted. In these cases, a new Cisco IOS software image has to be downloaded with Trivial File Transfer Protocol (TFTP) procedure from the ROMmon mode. Refer to the section Load the new software image with the TFTP server. Load the new software image with the TFTP server This section describes how to load a Cisco IOS software image from a TFTP server to the router flash memory. Use the procedure only for disaster recovery, as it erases all the datas that exist in flash memory before a new software image is downloaded to the router. Follow these steps to download a new software image to the router with a TFTP server. 1. First, you must set ROMmon environment variables prior to the TFTP download. All variable names are case sensitive. You can view the ROMmon environment variables by the the set command. rommon 1 >set PS1=rommon! > BOOT= WARM_REBOOT=FALSE?=0 BSI=0 RANDOM_NUM= RET_2_RTS=10:27:44 UTC Thu Jun RET_2_RCALTS= These variables are required to be set for TFTP download: IP_ADDRESS: The IP address for this router IP_SUBNET_MASK: The subnet mask for this router DEFAULT_GATEWAY: The default gateway for this router TFTP_SERVER: The IP address of the TFTP server in which the software image is stored TFTP_FILE: The software image filename to fetch 3. At the rommon: command prompt in the HyperTerminal window, type IP_ADDRESS= and press Enter. rommon 2 >IP_ADDRESS= Type IP_SUBNET_MASK= and press Enter. rommon 3 >IP_SUBNET_MASK= Type DEFAULT_GATEWAY= and press Enter. rommon 4 >DEFAULT_GATEWAY= Type TFTP_SERVER= and press Enter. rommon 5 >TFTP_SERVER= (6 of 10)11/30/ :21:09 PM

7 7. Type TFTP_FILE=/tftpboot/spak/c3825-adventerprisek9-mz b.bin and press Enter. rommon 6 >TFTP_FILE= /tftpboot/spak/c3825-adventerprisek9-mz b.bin 8. Type sync and press Enter. rommon 7 >sync Note: The "sync" command is required to write the monitor environment changes to NVRAM. 9. Type tftpdnld and press Enter. Enter y in response to the question do you wish to continue? y/n: [n]: in the output. rommon 8 >tftpdnld IP_ADDRESS: IP_SUBNET_MASK: DEFAULT_GATEWAY: TFTP_SERVER: TFTP_FILE: /tftpboot/spak/c3825-adventerprisek9-mz b.bin GE_PORT: Ge0/0 TFTP_MEDIA_TYPE: Copper GE_SPEED_MODE: Auto Invoke this command for disaster recovery only. WARNING: all existing data in all partitions on flash will be lost! Do you wish to continue? y/n: [n]:y Mac Address: a41.2cf0 Receiving /tftpboot/spak/c3825-adventerprisek9-mz b.bin from !!!!!!!!!! File reception completed. Copying file /tftpboot/c3825-adventerprisek9-mz b.bin to flash. Format: All system sectors written. OK... Format: Operation completed successfully. Format of flash: complete rommon 7 > 10. At the rommon prompt, type dir flash: to verify the software image downloaded on to the flash memory. rommon 7 >dir flash: (7 of 10)11/30/ :21:09 PM

8 Directory of flash: rw- c3825-adventerprisek9-mz b.bin Note: You have downloaded the new image c3825-adventerprisek9-mz b.bin onto the flash with the TFTP server. 11. Type boot flash:<filename> and press Enter to boot the router with the new CiscO IOS software image. rommon 8 > boot flash:c3825-adventerprisek9-mz b.bin program load complete, entry point: 0x , size: 0x2688b78 Self decompressing the image : ################################################# ################################################################################ ################################################################################ ######### [OK] Smart Init is enabled smart init is sizing iomem ----output truncated--- Router > 12. The router must now boot with the new Cisco IOS software image specified in the boot command and it must be in Router > prompt. Note: For Cisco 2600 Routers which run the ROM monitor command tftpdnld, the command reports a bad checksum comparison when it loads Cisco IOS software images of Cisco IOS Software Release 12.0(2.2)T or later. As a workaround to this problem, set the ROM monitor variable TFTP_CHECKSUM to 0. The variable TFTP_CHECKSUM=0 is defined from the ROM monitor set command, proceeded by the tftpdnld procedure. Next Step You have completed Recover your Access Point with the new software image. To continue the setup process, refer to Configure Your Router with Security Device Manager. To configure other devices in your network, refer to the Configuration Overview Page. Troubleshoot the Procedure This section provides information about common problems that you may encounter. If this information does not solve your problem, contact (8 of 10)11/30/ :21:09 PM

9 the SMB Technical Assistance Center (SMB TAC) for assistance. Problem Cause(s) and Suggested Solution(s) The router boots and displays several error messages but does not display a prompt in HyperTerminal. Press Enter to clear the output and display the router prompt. Follow these steps: You receive an error message Interface link did not come up. Timed out. TFTP: Operation terminated or Timed Out after you perform step 12 of the Load the new software image with the TFTP server section. 1. Ensure that the PC's IP address is configured with with a subnet mask of Refer to Configure an IP Address on Your PC for instructions. 2. Ensure that you use the proper cable. You must use a crossover cable not a straight-through cable to connect your PC to the router first Ethernet port. Refer to Cable Descriptions for more information. 3. Ensure that you have launched TFTP Server program. You receive an error message: TFTP error 1 received (File not found). TFTP: Operation terminated. Ensure that the new software image is stored in your TFTP Root directory and you have specified the correct file path in step 7 of Load the new software image with the TFTP server section. If you are still unable to complete the procedure successfully, contact the SMB Technical Assistance Center (SMB TAC) for assistance. Related Information Cable Descriptions Create a HyperTerminal Connection Configure an IP Address on Your PC Configure Your Router with Security Device Manager Cisco Systems, Inc. All rights reserved. Terms and Conditions, Privacy Statement, Cookie Policy and Trademarks of Cisco Systems, Inc. (9 of 10)11/30/ :21:09 PM

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