|You are talking about an alpha not a microvax with qbus?|
I think you should boot dua0 but I forget. B or boot is command to what is saved in the loader. If it has gone back to default then maybe that is way you see that.
You are trying to boot to a RRD42on the XMI bus.
There is some help in that microcode or boot os. I think help Don't let it boot or don't issue the boot command and then keep in it the loader. I can't take mine down right now to test that.
The best way to go is to get a version of the microcode loader and your exact model and get the docs for exact way to boot. Should still be able to boot over network maybe if drives have failed.
There might be some dec or alpha forums. I doubt a whole lot of people know about these. I stopped working on the microvax maybe 8 years ago. While we still have some alpha's they never break so I almost never repair them. They were $20K well spent.
1/3 of highway deaths are caused by drunks. The rest are by people who can't drive any better than a drunk.