Painting myself into a corner and working back out...

Upon leaving my friend's place in Indiana recently (see previous post) I brought back home with me an old iMac, a "blueberry", one of the blue-and-white cute cpu-and-monitor triangle shaped deals. It has a G3 processor and had a broken installation of OS 9. I recovered the important data and transferred it to a couple other media at my friend's place, then started tinkering. 

Having noticed the PPC disk in the OpenBSD distributions I decided to give it a go. Being the last to RTFM, as they say, I blithely blew away the machine's partitions and installed the usual set I'm used to with OpenBSD. The install went fine, but the machine could not be booted off the new OS at all. 

So I read. Don't delete the Mac's boot partition it says. The Mac ROM needs to see a HFS boot partition or it won't go nowhere. Drat. The first many resources I found all describe how to set up the installation presuming you knew this and presuming you were intending to make a dual-boot machine with Mac on the other side. Finally I did find a couple links which provided the clues needed about how to rectify the situation. Use pdisk to create an HFS ("Apple_HFS") partition of at least 1MB size named "boot", along with the other partitions usually used (/, swap, /tmp, /var/, /usr, /home). Then re-do the install. Then mount the OpenBSD install CD and the HD's boot partition and copy the open firmware program "ofwboot" to the "boot" partition. Finally, remove all CD's and boot with Command-option-o-f and issue the command 

boot hd:,ofwboot /bsd

Voilà, it works and I'm off and running :-)