From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx1.redhat.com (mx1.redhat.com [209.132.183.28]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id 5190221A16ED1 for ; Tue, 20 Jun 2017 11:10:16 -0700 (PDT) Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id A41007CE10; Tue, 20 Jun 2017 18:11:38 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com A41007CE10 Authentication-Results: ext-mx04.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx04.extmail.prod.ext.phx2.redhat.com; spf=pass smtp.mailfrom=lersek@redhat.com DKIM-Filter: OpenDKIM Filter v2.11.0 mx1.redhat.com A41007CE10 Received: from lacos-laptop-7.usersys.redhat.com (ovpn-116-150.phx2.redhat.com [10.3.116.150]) by smtp.corp.redhat.com (Postfix) with ESMTP id 099E66E516; Tue, 20 Jun 2017 18:11:37 +0000 (UTC) To: Rod Smith , edk2-devel@lists.01.org References: <30c8ed8a-9ed5-0472-acbe-1d8b17fb38fb@linaro.org> <46cef850-9a4f-b521-a379-037dae1d1a2b@redhat.com> <648c681f-008b-e483-dd93-38d8bccaeb61@rodsbooks.com> From: Laszlo Ersek Message-ID: <4e2544c2-3032-1aed-df3b-8b895286b358@redhat.com> Date: Tue, 20 Jun 2017 20:11:36 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.2.0 MIME-Version: 1.0 In-Reply-To: <648c681f-008b-e483-dd93-38d8bccaeb61@rodsbooks.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.28]); Tue, 20 Jun 2017 18:11:38 +0000 (UTC) Subject: Re: How can we identify an ISO file is an EFI bootable ISO image? X-BeenThere: edk2-devel@lists.01.org X-Mailman-Version: 2.1.22 Precedence: list List-Id: EDK II Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 20 Jun 2017 18:10:16 -0000 Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit On 06/20/17 19:36, Rod Smith wrote: > On 06/20/2017 12:47 PM, Laszlo Ersek wrote: >> For UEFI boot, only the ElTorito image matters. > > MOSTLY, yes; however, some EFI implementations include ISO-9660 drivers. > This is definitely true of the EFI used by VirtualBox. I think I've seen > this feature on one or two UEFI-based PCs, too, but I don't recall the > details and I can't say I'm 100% certain of this. There are also > ISO-9660 drivers floating around that can be loaded from a FAT > partition. In either of these cases, the files on the ISO-9660 > filesystem can be used to boot from an optical disc, even if it lacks > the El Torito image. Good point! > This is admittedly a corner case at best; but IMHO it's worth keeping in > mind, since non-matching El Torito and ISO-9660 files could lead to user > (or developer) confusion. That has actually tripped up at least one OVMF user in the past; they had some inconsistency between the two locations. The problem was originally reported in ("OvmfPkg: UEFI Shell only sees EFI\BOOT\BOOTX64.EFI"), but now that the edk2 github issue tracker is gone, the ticket cannot be viewed even in read-only mode. :/ Thanks! Laszlo