What Is Rommon Mode
Perform these steps to configure the router to boot up in ROM monitor mode the next time it is.u upgrade ROMMON, System will reboot after upgrade.
For help.rommon #0Now I know what ROMMON is, it’s the base operating system of the device, its job is a bit like the BIOS on a PC, it locates and loads the operating system. The only time you should ever see a rommon prompt is. If you ‘force’ a device into rommon mode as it boots. The devices config register is incorrectly set. The operating system is missing/corrupt.
Meade dsi drivers for mac. The flash memory of the device is broken, (or needs reformatting).Chances are, the firm who ‘re-sold’ them simply did some, and forgot to set the config register back again. SolutionI’ve recovered enough passwords and enough times to know that if the OS is present on the device, I can load it manually with the ‘boot’ command.
Hi,The switch could wind up in ROMmon mode due to these reasons,. A switch reload or crash after the image was corrupted or deleted. The Compact Flash which holds the system image has been removed. The configuration register has been changed incorrectly.
The configuration register value of 0x0 always brings the switch to ROMmon mode. The typical configuration register is 0x2102, with the boot system flash command pointing to the system image to load. The boot variable is incorrect, but a valid image is still presentIn our case, config register is set correctly as 0x2102, I would suggest you to verify the boot variable.1. When the switch gone into rommon, Issue the dir bootflash: command to list the files present in the bootflash, or issue the dir slot0: command to list the files present in the Compact Flash device.rommon 1 dir bootflash:rommon 2 dir slot0:Note: The reason the switch reboots continuously is because the system image file name specified does not exist, but there is a valid file in the bootflash and slot0. Also, the system image file name specified is case sensitive. If it is not specified correctly, it causes a continuous reboot.2. The system is back up, Issue the dir bootflash: command to note the file in the bootflash.
Issue the dir slot0: command if you loaded the system file present in the slot0.Issue the show bootvar command to check the current boot variable.example:Switch# show bootvarBOOT variable = bootflash:cat4000-is-mz.121-8a.Ew,1CONFIGFILE variable does not existBOOTLDR variable does not exist3. Remove the existing incorrect boot variable and add the correct one. Issue the configure terminal command in order to do this.Switch# configure terminalEnter configuration commands, one per line. End with CNTL/Z.Switch(config)# no boot system flash bootflash:cat4000-is-mz.121-8a.EwSwitch(config)# boot system flash bootflash:cat4000-is-mz.121-11b.EWSwitch(config)# end4. Save the configuration from running to startup, by issuing the write memory command.Switch# write memoryBuilding configuration.Compressed configuration from 4359 bytes to 1730 bytesOK5. Check the boot variable again to make sure it is set properly so that the switch boots up the correct system file on the next rebootRefer:Regards,Aru.
Please rate if the post is useful. Hi,The switch could wind up in ROMmon mode due to these reasons,. A switch reload or crash after the image was corrupted or deleted.
The Compact Flash which holds the system image has been removed. The configuration register has been changed incorrectly. The configuration register value of 0x0 always brings the switch to ROMmon mode. The typical configuration register is 0x2102, with the boot system flash command pointing to the system image to load. The boot variable is incorrect, but a valid image is still presentIn our case, config register is set correctly as 0x2102, I would suggest you to verify the boot variable.1. When the switch gone into rommon, Issue the dir bootflash: command to list the files present in the bootflash, or issue the dir slot0: command to list the files present in the Compact Flash device.rommon 1 dir bootflash:rommon 2 dir slot0:Note: The reason the switch reboots continuously is because the system image file name specified does not exist, but there is a valid file in the bootflash and slot0.
Also, the system image file name specified is case sensitive. If it is not specified correctly, it causes a continuous reboot.2. The system is back up, Issue the dir bootflash: command to note the file in the bootflash. Issue the dir slot0: command if you loaded the system file present in the slot0.Issue the show bootvar command to check the current boot variable.example:Switch# show bootvarBOOT variable = bootflash:cat4000-is-mz.121-8a.Ew,1CONFIGFILE variable does not existBOOTLDR variable does not exist3. Remove the existing incorrect boot variable and add the correct one. Issue the configure terminal command in order to do this.Switch# configure terminalEnter configuration commands, one per line.
End with CNTL/Z.Switch(config)# no boot system flash bootflash:cat4000-is-mz.121-8a.EwSwitch(config)# boot system flash bootflash:cat4000-is-mz.121-11b.EWSwitch(config)# end4. Save the configuration from running to startup, by issuing the write memory command.Switch# write memoryBuilding configuration.Compressed configuration from 4359 bytes to 1730 bytesOK5.
Check the boot variable again to make sure it is set properly so that the switch boots up the correct system file on the next rebootRefer:Regards,Aru. Please rate if the post is useful. Hi ArumugamFirst, thanks a lot for your help.I understand that if my image is corrupted or deleted, it will be impossible to start with a 'boot' command from the rommon mode.I have no device available on slot0 and my config-register is 0x2102, so my problem must be an incorrect boot variable.The result of show botvar isSwitch#show bootvarBOOT variable = variable does not existCONFIGFILE variable does not existBOOTLDR variable does not existconfigure-register is 0x2102I think that i will must set my boot variable. If yes, how must i do it?Thanks againMarcelo.