Mainframe OSAs and trigger BPDU guard and error disables switch port

When you upgrade microcode on IBM OSAs when they come back up they may act as a 'bridge' and send BPDUs to your switch which fires bpudguard. You do not want to change the switch. what you have done is have the mainframe people stop and start the OSA, make sure the UCB is not 'boxed', and you should be fine.