I have several PMAC(1)s that I want to upgrade firmware on. The processor is a PMAC Universal CPU with OPT-16, so they have a battery. When I try to put them in bootstrap mode, installing J4 on the CPU board, nothing happens. PEWIN 32 Pro2 just starts to communicate and does not recognize the jumper is on. All the firmware upgrade documents say this is the procedure. How do I upgrade the firmware?