Re: CTF: UEFI HTTP boot support

From: Simon J. Gerraty <>
Date: Tue, 16 Jun 2020 09:26:20 -0700
Rodney W. Grimes <> wrote:
> > Are you refering to something like:
> >
> > vfs.root.mountfrom="cd9660:/dev/md0.uzip"
> >
> > we boot that way all the time.
> What provides the cd9660 driver to FreeBSD?  When you load the .iso
> over a network card, aka PXE/HTTP, the code that does that usually
> creates a ram disk and a "fake cd drive" that stops working as soon

We don't use PXE much except in a bringup lab, and then I think we use
NFS for rootfs.

Normally if iso is comming from network it is to do an install
eg loader is doing 'install tftp://host/install.tar'

The "fake cd drive" is in the kernel, loader just copies the iso into
memory like any other module, and by the time that's done you just
reboot into the newly installed system, which again uses


but in that case the rootfs is an iso image on local disk.

The rootfs iso is minimal - enough to fsck and mount real media
and initialize Verified Exec.
It improves our chances of being able to recover from severe disk
corruption after cleaning lady pulls the cord, to vaccuum ;-)

Received on Tue Jun 16 2020 - 14:26:28 UTC

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