1.\" Copyright (c) 2018 iXsystems, Inc. 2.\" All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 13.\" THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND 14.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 15.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 16.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE 17.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 18.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 19.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 20.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 21.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 22.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 23.\" SUCH DAMAGE. 24.\" 25.\" $FreeBSD$ 26.\" 27.Dd March 30, 2018 28.Dt ISOBOOT 8 29.Os 30.Sh NAME 31.Nm isoboot 32.Nd Boot code for hybrid ISO/USB images on BIOS-based computers 33.Sh DESCRIPTION 34.Nm 35is used on BIOS-based computers to boot from an ISO image that has 36been written to a USB flash drive or other HDD-like device. 37.Nm 38is installed in a 39.Cm freebsd-boot 40partition with 41.Xr mkimg 1 . 42.Sh IMPLEMENTATION NOTES 43The El Torito standard for bootable CDs provides a 32KB "System Area" 44at the beginning of an image. 45To create an image that is able to be booted by the BIOS as either a 46CD-ROM ("ISO") and as a more HDD-like image (e.g. on a USB flash drive) 47it is necessary to have both a standard El Torito boot catalog 48containing a HDD-style partition table and boot code. 49.Nm 50is intended to be placed in a GPT partition to allow the system to find 51the standard 52.Fx 53.Xr loader 8 54in the ISO filesystem later in the image. 55.Sh BOOTING 56.Nm 57looks for an ISO filesystem image on the device it was booted from and 58seeks to read either the primary 59.Fx 60.Xr loader 8 61or kernel from there. 62.Sh SEE ALSO 63.Xr mkimg 1 64.Sh HISTORY 65.Nm 66appeared in FreeBSD 12.0. 67.Sh AUTHORS 68This manual page written by 69.An Benno Rice Aq benno@FreeBSD.org . 70