What a day.. 12 hours fiddling. When the z is good, it's GOOD. BUT when I start to fiddle... We grow through pain.
To cut the story short, I replaced the HD in my 3100 with a CF. I couldn't format the card on my desktop (another nightmare story) so I thought I'd just throw it in and see what happened.
After discovering the console in the bootloader (by pressing D+B after power is added - for a long time), I set the CF to the correct HDD1/2/3 values using fdisk (HDD1=1-20,83 HDD2=21-40,83 HDD3=41+ c). At last, I could now get it to boot, but only when I choose "restore the hard disk" (or whatever it's called in the startup menu thing) - a standard try at booting just ends in the message, "Hard disk not initialised". Well, at least it kind of boots.
OK, another 6 hours before bed - I can do this.
I then found the reason. The Z doesn't want to give you the time of day unless HDD1 and HDD2 have a few tiny, pointless files in a directory called ".sys", so I downloaded them with the intention of finishing this madness and getting some sleep (Trisoft, my hero).
And this is where I stand now. I've got the files, I've got a machine that can eventually boot normally (with a bit of fiddling), and I can even write normally to HDD3, but I have absolutely NO idea how to copy the files onto HDD1/2 on the card. Everytime I try to write to the card it says "Read only file system" GRRRRRH!HHHHHR!!!!!"$!"#$RSDAF!!!!!! are you doing this deliberately? I was VERY close to demonstrating Newtons laws with the Z and a concrete floor.
2:40am, I've had enough. How do I write those tiny little files to HDD1/HDD2 without it moaning at me? Is there a magic command that makes a filesystem read/write? and why oh why does HDD3 work! It's teasing me, isn't it. Playing with me for kicks.