# Running FreeBSD 11 on an imac with ATI graphics



## rdeiriar (Jan 19, 2018)

I inherited an oldie at work today, an imac 27 inch core i5 (Model number 11.1) and want to share a few tips in order to get FreeBSD 11.1 running on it

This model has an early UEFI Bios, an ATI Mobility Radeon 4850 graphics card and a nasty video firmware bug that made it useless with everything i threw at it (FreeBSD 11.1, Ubuntu-16.04.3 Desktop and Server, Debian 9) with variations of the same failure, namely, a blank display (FreeBSD at least displayed the console, the Linuxes (Kernels 4.4, 4.13 and 4.14) went blank immediately after boot)

Getting Xorg to run on the integrated display (the whole point of reusing this computer) seemed impossible, the driver insisted in getting the internal and external outputs mixed up, then i remembered reading, many years ago, the following piece of advice

'An Intel based Mac loads a fairly complete legacy BIOS if it boots from an MBR disk'

And, for some reason, this BIOS does not trigger (or fixes ?) the bug that mixes up the display ports. Thus, the solution, as in my case i did not intended to dual boot OS X, was to wipe the disk, UEFI partition included, and do an MBR style install following these instructions

http://daemon-notes.com/articles/system/install-zfs/begin

Skipping the part about building a ZFS mirror

Then i installed the system directly from /usr/freebsd-dist, rebooted, and ... after installing xorg and xf86-video-ati i have a fully functional desktop, hardware acceleration included.

If anyone is interested, i can do a detailed writeup of the procedure

Of note, an easier way could be to use the installer, selecting to manually create an MBR partition and ignore the warnings about the system not being MBR-bootable.

I understand that other ATI equipped Macbook's and iMacs have the same problem, an MBR based install should help on these as well


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## fernandel (Jan 19, 2018)

I ma running FreeBSD on the same iMac (dual boot for now) and works without problems except sound. It works from the speaker or from the headphones but not both. If I have settings that works both than  when I connect headphones I hear frpm the speakers and the headphones.


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