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Date:      Fri, 6 Nov 2020 15:13:43 +0000
From:      Bob Bishop <rb@gid.co.uk>
To:        Poul-Henning Kamp <phk@phk.freebsd.dk>
Cc:        hackers@freebsd.org
Subject:   Re: Have trick, not sure where to document...
Message-ID:  <0BAC0602-9CA6-4C5B-8AA7-46986714C8CF@gid.co.uk>
In-Reply-To: <57254.1604658230@critter.freebsd.dk>
References:  <57254.1604658230@critter.freebsd.dk>

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Hi,

> On 6 Nov 2020, at 10:23, Poul-Henning Kamp <phk@phk.freebsd.dk> wrote:
>=20
> I had some trouble with a particular remote site, and wanted to have
> the hardware watchdog protect the boot-sequence, but the BIOS had no
> support for this.
>=20
> The solution I found was to use the UEFI shell to arm the watchdog
> before the actuall boot.
>=20
> After digging around in the abysmal UEFI ecosystem some time, I ended
> up with a bunch of "MM" commands in startup.nsh, before it launches
> BOOTx64.efi:
>=20
> 	MM 4e ;IO :87 -n
> 	MM 4e ;IO :87 -n
> 	MM 4e ;IO :20 -n
> 	MM 4f ;IO -n
> 	MM 4e ;IO :21 -n
> 	MM 4f ;IO -n
> 	[...]
> 	MM 4e ;IO :aa -n
> 	BOOTx64.efi
>=20
> This seems like a genuinely useful trick to have in the tool-box
> and now I'm trying to find out where in our documentation something
> like this belongs ?
>=20
> It seems too specialized and with too many sharp edges for the =
handbook ?
>=20
> Wiki/UEFI seems rather historical...
>=20
> Suggestions ?

boot(8). If that is deemed inappropriate, then boot(8) should definitely =
have a reference to the actual place.

> --=20
> Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
> phk@FreeBSD.ORG         | TCP/IP since RFC 956
> FreeBSD committer       | BSD since 4.3-tahoe
> Never attribute to malice what can adequately be explained by =
incompetence.
> _______________________________________________
> freebsd-hackers@freebsd.org mailing list
> https://lists.freebsd.org/mailman/listinfo/freebsd-hackers
> To unsubscribe, send any mail to =
"freebsd-hackers-unsubscribe@freebsd.org"
>=20

--
Bob Bishop
rb@gid.co.uk







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