I am working at a client site and I need to upgrade the IOS running on a Single Sup II+ engine running in a 4500 Switch chassis. I have searched Cisco specific to the 4500 and I do not get anything back that is specific to performing an IOS upgrade on a Sup II+.
I had an issue with this the last time I tried it about a year ago. I want to make sure I do this properly this time.
As others indicated, this step was included in the document to prevent customers from getting into rommon mode due to previous incorrect config register setting.