I have a 2010 imac, which shows under apple's info as
iMac (21.5-inch, Mid 2010)
Model Identifier: iMac11,2
Processor Name: Intel Core i3
Processor Speed: 3.06 GHz
Number Of Processors: 1
Total Number Of Cores: 2
L2 Cache (per core): 256 KB
L3 Cache: 4 MB
Memory: 4 GB (since updated to 12G)
MC508LL/A
A1311 (EMC 2389)
and I think the disk is mostly failed (working but about 1 xfer/s under
macOS) and am trying to use NetBSD to diagnose the problem more reliably.
(I tried to boot off an SSD that had MBR boot on it and it was not
recognized. It seems that even this machine must be EFI only for disks.)
II tried the 9.2 iso from
http://cdn.netbsd.org/pub/NetBSD/NetBSD-9.2/images/NetBSD-9.2-amd64.iso
by burning it to a CD-R and powering up the mac holding option which got
me two cd icons, labeled "windodws" and "EFI boot". double clicking on
EFI, I got the netbsd boot prompt, kernel messages, resize to full
screen but still text, all as expected.
Shortly after printing out about root on something and kerninfo, after
what felt like most of the boot messages, the screen went black and the
CD kept making noise for maybe 30s and I never got a display. Looking
at another box's dmesg, this seems 99% likely to be trying to do
drm/radeon. The web says this model has
ATI Radeon HD 4670
This feels like a DRM/video bug. I'm not really sure what needs to be
disabled, and I'm guessing
userconf disable radeon*
might be the right incantation (I tried "userconf no radeon0" without
reading the docs, and that didn't work, but now I am no longer puzzled
by that...).
If anyone is running 9 on an imac of around that vintage and either 1)
doesn't need to disable radeon/drm 2) or has a tested incantation to
turn it off, I'd appreciate knowing it. Or if current works, but really
I just want to poke around in console mode, run dd, and so on.
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