Read the Release Notes and determine if the ROMMON requires to be upgraded or not.
Do not listen to the hype about ISSU, FSU/eFSU/xFSU.
If-and-when ISSU/FSU/eFSU works, it is great. However, if and when ISSU/FSU/eFSU doesn't work, you need physical access to either one of the two units to power off the boot loop. And once you kill the second unit, you still need to figure out what IOS version both units will boot into. Again, not a pretty sight to see.
Ok, so this is how we've "formulated" the method to upgrade the ROMMON and the IOS in one reboot/reload:
NOTE: 4500X IOS-XE comes in two file extensions: BIN or TAR. Make sure to get the TAR file extension!
1. Upload the IOS-XE to the active unit: archive tar /x tftp://<TFTP IP_Address>/IOS_filename.tar bootflash:
2. Upload the IOS-XE to the secondary unit: archive tar /x tftp://<TFTP IP_Address>/IOS_filename.tar slavebootflash:
3. Copy the ROMMON file to the active unit: copy ftp://<TFTP IP_Address>/IOS_filename bootflash:
4. Copy the ROMMON file to the secondary unit: copy ftp://<TFTP IP_Address>/IOS_filename slavebootflash:
5. Change the boot variable string: Remove all the "old" boot variable string, insert a new boot variable string to point to the ROMMON file, point another boot variable string to point to the NEW IOS and then put another boot variable string to point to the old IOS
conf t
no boo system bootflash:old_ios.bin
boot system bootflash:ROMMON_filename
boot system bootflash:NEW_IOS_filename.bin
boot system bootflash:OLD_IOS_filename.bin
end
6. Make sure boot variable string is "0x2102"
7. Save the config
8. Reboot
OPTIONAL:
1. Check the MD5 hash of the IOS files (including the ROMMON) using the command "verify /md5 bootflash:filename.bin <MD5 hash from the Cisco website>"
2. Backup the config to somewhere external.
Hope this helps.
