[Baphijmm]

Posting again for an update:

Thought I'd downloaded OpenBSD before I left; turns out I downloaded FreeBSD. It fails to boot, citing an inability to load the OBP console. Will try OpenBSD tomorrow.

Solaris 9 was actually my first go-to as an alternate means of trying to format this disk, because of the aforementioned post; I'd seen it before, and figured the correct information might just be on that disk. Alas, my copy of it won't boot on that machine either; it boots up normally at first, but when it gets to the Java "Netscape browser" portion of the install, it basically just sits there. I've let it sit literally overnight in the hopes that something might change, but no such luck. It's definitely the SPARC version, and the version I used to load 9 onto my Ultra 1, so it's not a disk problem I don't think.

The Solaris 10 disk does not have the SUN72G option, or else I would have tried it. There is no correct option on the boot disk, meaning the literal only way to get this silly thing to format is to know the topology of the drive.