iBook seems happier today. I figured out which boot settings to use to prevent the freezes; eventually I will make those settings permanent in yaboot.conf.
I also found out how upgradeable this box is even today: up to 1,25 GB RAM and SSDs up to 480 GB with the required parts available from a specialist store. The RAM upgrade will probably happen in the next few weeks; the SSDs are somewhat pricey and I'll need to think on it.
@Reinderdijkhuis I thought the RAM was soldered on to the iBook. You got the guts to go at it with a soldering iron? I surrendered my daughter’s iBook to the Goodwill computer store when the ram on the mobo went bad.
@Devils_Rancher It's been a while since I've seen this done (if I ever did actually see it! My memory is a bit hazy on this front after 10+ years), but as I recall there are two RAM slots and the second one can be inserted normally. But thanks for the heads-up! I will read/watch instructions before ordering so I know what needs to be done.
@Reinderdijkhuis Ah, you are correct, 256 mb soldered on plus 1 expansion slot. I have heard of people removing the on-board RAM when it went bad, but had forgotten the slot. So many Macs lost to the sands of time...