From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from lists.gentoo.org (pigeon.gentoo.org [208.92.234.80]) by finch.gentoo.org (Postfix) with ESMTP id 863FF138E74 for ; Tue, 2 Sep 2014 12:30:37 +0000 (UTC) Received: from pigeon.gentoo.org (localhost [127.0.0.1]) by pigeon.gentoo.org (Postfix) with SMTP id 6D060E0CCC; Tue, 2 Sep 2014 12:30:28 +0000 (UTC) Received: from lyseo.edu.ouka.fi (unknown [82.128.138.2]) by pigeon.gentoo.org (Postfix) with ESMTP id E772DE0CBB for ; Tue, 2 Sep 2014 12:30:26 +0000 (UTC) Received: from [10.171.59.149] (85-76-46-148-nat.elisa-mobile.fi [85.76.46.148]) (using TLSv1 with cipher AES128-SHA (128/128 bits)) (No client certificate requested) by lyseo.edu.ouka.fi (Postfix) with ESMTPSA id A2C1E193F981 for ; Tue, 2 Sep 2014 15:30:09 +0300 (EEST) Subject: Re: [gentoo-user] making bootable USB References: <20140830053737.GA5867@syscon2> <20140902010802.70b66b75@digimed.co.uk> <20140902002605.GJ15640@syscon7> <201409020636.17608.michaelkintzios@gmail.com> <20140902055515.GL15640@syscon7> From: Matti Nykyri Content-Type: text/plain; charset=us-ascii X-Mailer: iPhone Mail (11D201) In-Reply-To: <20140902055515.GL15640@syscon7> Message-Id: <2A6E3C95-467D-4053-A2B9-AFD9DAB0D727@iki.fi> Date: Tue, 2 Sep 2014 15:29:48 +0300 To: "gentoo-user@lists.gentoo.org" Content-Transfer-Encoding: quoted-printable Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-Id: Gentoo Linux mail X-BeenThere: gentoo-user@lists.gentoo.org Reply-to: gentoo-user@lists.gentoo.org Mime-Version: 1.0 (1.0) X-Archives-Salt: 10627452-2851-4f77-a786-ecf5691bc25a X-Archives-Hash: d0dd2457dce15994792ea8be0eb945ef > On Sep 2, 2014, at 8:55, Joseph wrote: >=20 >> On 09/02/14 06:36, Mick wrote: >>> On Tuesday 02 Sep 2014 01:26:05 Joseph wrote: >>> On 09/02/14 01:08, Neil Bothwick wrote: >>> >On Mon, 1 Sep 2014 17:42:47 -0600, Joseph wrote: >>> >> I just tried "usb_instal.sh" script from systemrescuecd-x86-4.3.0.iso= >>> >> and my box boots just fine. So why do I have problem using "unetbooti= n" >>> >> and generating bootable USB manually. >>> > >>> >unetbootin uses some $MAGIC that doesn't work with all ISOs. isohybrid >>> >seems to work with everything and is much simpler to use too. >>>=20 >>> I just tried it as root: >>> isohybrid install-amd64-minimal-20140828.iso >>> dd if=3D/home/joseph/Downloads/install-amd64-minimal-20140828.iso of=3D/= dev/sda >>> bs=3D4096 sync >>>=20 >>> And the USB still can not boot it :-/ >>=20 >> This is rather strange. >>=20 >> What do you see when you run >>=20 >> fdisk -l /dev/sda >>=20 >> *after* you have completed dd and sync as you show above? >>=20 >> --=20 >> Regards, >> Mick >=20 > Yes, indeed I find it very strange as well. > I just re-run the dd on my faster box. >=20 > dd if=3D/home/joseph/Downloads/install-amd64-minimal-20140828.iso of=3D/de= v/sdb bs=3D4096 > 48640+0 records in > 48640+0 records out > 199229440 bytes (199 MB) copied, 318.573 s, 625 kB/s > sync >=20 > fdisk -l /dev/sdb >=20 > Disk /dev/sdb: 960 MiB, 1006632960 bytes, 1966080 sectors > Units: sectors of 1 * 512 =3D 512 bytes > Sector size (logical/physical): 512 bytes / 512 bytes > I/O size (minimum/optimal): 512 bytes / 512 bytes > Disklabel type: dos > Disk identifier: 0x1047d058 >=20 > Device Boot Start End Blocks Id System > /dev/sdb1 * 0 389119 194560 17 Hidden HPFS/NTFS >=20 > --=20 > Joseph Hi, Just wanna say few words to clarify few things about bootstraping. If you kn= ow what you are doing, this all is very simple. What you need for a working system is a working root filesystem that contain= s all the scripts, modules and executables. A minimal cd contains this. You c= ould also use stage3 tar ball. Then you need a working kernel image and possibly a initrd. There is a worki= ng kernel on minimal cd. All begins with boot loader. That loader is loaded by BIOS first. Then boot l= oader starts executing and loads kernel with right parameters. Kernel takes o= ver and loads rootfs and so on. On normal disk (USB, sata, ATA, SCSI (and DVD i think)) you have a normal MB= R (first 512 bytes of disk) which BIOS loads to 0x07C0 address in memory and= starts executing. So just install boot loader (like grub) to the beginning o= f the disk and it will boot. With right commands/config you can load the ker= nel correctly and boot. CD is different. BIOS can't read ISO file system. For CD boot you will need t= o create image of a floppy-disk and install your boot loader into that image= . The boot loader has to have drivers to read the real ISO file system so th= at it can load the kernel into memory and boot. Because of this a plain cd i= soimage is unbootable although all necessary stuff is there. It is easily ar= ranged so that it becomes a bootable USB disk. --=20 -Matti =20=