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Date:      Fri, 21 Jul 2017 10:08:29 +0100
From:      Matthew Seaman <>
Subject:   Re: UEFI and FreeBSD-11
Message-ID:  <>
In-Reply-To: <>
References:  <>

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From: Matthew Seaman <>
Message-ID: <>
Subject: Re: UEFI and FreeBSD-11
References: <>
In-Reply-To: <>

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On 07/21/17 01:02, James B. Byrne via freebsd-questions wrote:
> My CentOS-6 based workstation is dying a slow death due to bit rot and
> so I decided to swap out the existing disc drive for another.  Given
> that I had to reinstall anyway I decided that now was the time to try
> out FreeBSD-11 as a desktop.
> This Intel based system had UEFI enabled.  Apparently this may have a
> surprising, to me, effect on the video display used for the system
> console in text mode.  For whatever reason the boot process insists on
> treating a 480x640 60Hz display as 800 x 480 at some other refresh
> rate, probably 75Hz.  This produces a difficult to read flickering
> display and oddball presentation artifacts such as typing at a cursor
> presented mid way from the top over existing text and displaying the
> output at the bottom of the screen.
> Is this a known phenomenon? Is there something that I am supposed to
> do to get this to work properly or do I just disable UEFI?

UEFI is meant to be supported, but I think it is fair to say that UEFI
support in FreeBSD has not had anything like the exposure that UEFI has
had on other systems, and that the FreeBSD UEFI support still has work
to be done.

If your system supports MBR instead, then switching to that will give
you a much pleasanter experience.

On the other hand, contributions to debugging UEFI support would be
gratefully received.  A quick google shows that this sort of problem is
fairly common for all sorts of different combinations of hardware, BIOS
and OS.  For instance:

If you're still having trouble, then I suggest asking on
freebsd-hackers@ as that's more likely to get you in touch with the
people that are developing UEFI support.




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