From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from eastrmfepo101.cox.net (eastrmfepo101.cox.net [68.230.241.213]) by ml01.01.org (Postfix) with ESMTP id 984C921962338 for ; Tue, 20 Jun 2017 10:35:34 -0700 (PDT) Received: from eastrmimpo210.cox.net ([68.230.241.225]) by eastrmfepo101.cox.net (InterMail vM.8.01.05.28 201-2260-151-171-20160122) with ESMTP id <20170620173656.ZALX20836.eastrmfepo101.cox.net@eastrmimpo210.cox.net> for ; Tue, 20 Jun 2017 13:36:56 -0400 Received: from nessus.rodsbooks.com ([72.209.58.79]) by eastrmimpo210.cox.net with cox id b5cw1v00G1iZxRU015cwbY; Tue, 20 Jun 2017 13:36:56 -0400 X-CT-Class: Clean X-CT-Score: 0.00 X-CT-RefID: str=0001.0A020203.59495D38.0229, ss=1, re=0.000, recu=0.000, reip=0.000, cl=1, cld=1, fgs=0 X-CT-Spam: 0 X-Authority-Analysis: v=2.1 cv=QKHmR27L c=1 sm=1 tr=0 a=z3VlLZBMWEV9qHpJH5brsw==:117 a=z3VlLZBMWEV9qHpJH5brsw==:17 a=L9H7d07YOLsA:10 a=9cW_t1CCXrUA:10 a=s5jvgZ67dGcA:10 a=VuW-04m-3F0A:10 a=IkcTkHD0fZMA:10 a=LWSFodeU3zMA:10 a=28bguoTQAAAA:8 a=uG3wxwoigm8gFIzBaHgA:9 a=QEXdDO2ut3YA:10 a=voRV_PY5qW-4FQMV9MBC:22 X-CM-Score: 0.00 Authentication-Results: cox.net; none Received: from [192.168.1.2] (nessus.rodsbooks.com [192.168.1.2]) by nessus.rodsbooks.com (Postfix) with ESMTP id 5E5B92A01C6 for ; Tue, 20 Jun 2017 13:36:56 -0400 (EDT) To: edk2-devel@lists.01.org References: <30c8ed8a-9ed5-0472-acbe-1d8b17fb38fb@linaro.org> <46cef850-9a4f-b521-a379-037dae1d1a2b@redhat.com> From: Rod Smith Message-ID: <648c681f-008b-e483-dd93-38d8bccaeb61@rodsbooks.com> Date: Tue, 20 Jun 2017 13:36:56 -0400 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.1.1 MIME-Version: 1.0 In-Reply-To: <46cef850-9a4f-b521-a379-037dae1d1a2b@redhat.com> 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 17:35:35 -0000 Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit On 06/20/2017 12:47 PM, Laszlo Ersek wrote: > On 06/20/17 14:34, Heyi Guo wrote: > >> Several tools like mount in Linux will show all files together >> including EFI/BOOT directory, > > That directory, displayed as part of the ISO9660 filesystem that was > written to the ISO image / CD-ROM, is entirely irrelevant when it comes > to UEFI-bootability. I doesn't even need to exist, and if it does, it's > likely there only for convenience reasons (so that people don't have to > run "dumpet" or similar tools to extract the FAT image first, and then > the EFI binaries second, if they want to investigate the EFI binaries). > > 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. 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. -- Rod Smith rodsmith@rodsbooks.com http://www.rodsbooks.com