From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Thomas Schmitt" Subject: Re: ISO installer image: GPT versus MBR partitions Date: Sun, 21 Apr 2019 13:16:14 +0200 Message-ID: <147867275872258208@scdbackup.webframe.org> References: <20190421075847.ka4aeseg6kgfufz4@pelzflorian.localdomain> Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Return-path: Received: from eggs.gnu.org ([209.51.188.92]:38675) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hIAQ7-0003sa-DX for guix-devel@gnu.org; Sun, 21 Apr 2019 07:14:04 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hIAQ6-0002IX-ET for guix-devel@gnu.org; Sun, 21 Apr 2019 07:14:03 -0400 In-Reply-To: <20190421075847.ka4aeseg6kgfufz4@pelzflorian.localdomain> List-Id: "Development of GNU Guix and the GNU System distribution." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: guix-devel-bounces+gcggd-guix-devel=m.gmane.org@gnu.org Sender: "Guix-devel" To: bug-xorriso@gnu.org Cc: guix-devel@gnu.org Hi, i plan to ask at gru-devel about mformat, its MBR, and the partition entry= , as soon as the last experiment is made (LBA 1 rather than LBA 0 as start of the inner partition). For that discussion i could also need the exact model name of the Macbook. If its EFI has a name, then this too. Florian Pelz wrote: > +--- grub-2.02/util/grub-mkrescue.c 2019-04-21 08:17:18.880000000 +0= 200 > ++++ grub-2.02/util/grub-mkrescue.c 2019-04-21 08:17:52.588000000 +0= 200 > [...] > +- { "mformat", "-C", "-f", "2880", "-L", "16", > ++ { "mformat", "-k", "-C", "-f", "2880", "-L", "16", The difference between the contents of the first image block with and without option -k is significant, at least if we ask program "file". If a special version of gub-mkrescue is acceptable, then i would rather propose to apply the dd treatment to efiimgfat after mformat created it without option -k. We could ask at grub-devel for advise how to write 16 bytes to that file without needing another shell command. (It's C language, after all.) The binary differences between both blocks 0, except partition entry, are: /efi.img from Guix 0.16.0 ######################### Image from mformat -k 00000000 : eb 3c 90 4d 54 4f 4f 34 30 32 31 00 02 01 01 = 00 ### ### ### ### ### ### ### ### ### ### ### 00000000 : 00 00 00 00 00 00 00 00 00 00 00 00 02 01 01 = 00 00000020 : 00 00 00 00 00 00 29 a7 48 66 33 4e 4f 20 4e = 41 ### ### ### ### 00000020 : 00 00 00 00 00 00 29 42 87 4b 7d 4e 4f 20 4e = 41 00000030 : 4d 45 20 20 20 20 46 41 54 31 32 20 20 20 fa = 31 ### #= ## 00000030 : 4d 45 20 20 20 20 46 41 54 31 32 20 20 20 00 = 00 00000040 : c0 8e d8 8e c0 fc b9 00 01 be 00 7c bf 00 80 = f3 ### ### ### ### ### ### ### ### ### ### ### ### #= ## 00000040 : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 = 00 00000050 : a5 ea 56 00 00 08 b8 01 02 bb 00 7c ba 80 00 = b9 ### ### ### ### ### ### ### ### ### ### ### #= ## 00000050 : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 = 00 00000060 : 01 00 cd 13 72 05 ea 00 7c 00 00 cd 19 00 00 = 00 ### ### ### ### ### ### ### ### ### 00000060 : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 = 00 ... 000001f0 : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 55 = aa ### #= ## 000001f0 : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 = 00 Have a nice day :) Thomas