If after checking feature 59 the 6.0 went through ok, what did you mean by the part after that - "if that is the case, then you can back up your programming, then swap the processors and restore from your card"?
Before I take the system down I would do a manual backup, then if the 6.0 upgrade doesn't work out, could I power off, put the backup card back in and start back up and do a restore? Wasn't sure how much of a risk I would run, ending up with a system that was half upgraded and not working...