From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from list by lists.gnu.org with archive (Exim 4.71) id 1hOzgW-0004ET-6V for mharc-grub-devel@gnu.org; Fri, 10 May 2019 03:11:12 -0400 Received: from eggs.gnu.org ([209.51.188.92]:48374) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hOzgT-0004E4-I3 for grub-devel@gnu.org; Fri, 10 May 2019 03:11:10 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hOzgS-00079T-Gf for grub-devel@gnu.org; Fri, 10 May 2019 03:11:09 -0400 Received: from mout.gmx.net ([212.227.15.19]:33733) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1hOzgS-00078r-6F for grub-devel@gnu.org; Fri, 10 May 2019 03:11:08 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=gmx.net; s=badeba3b8450; t=1557472266; bh=DN1ktMROE999F0/vU85rQiBA4Epya1ltWpMqI2+qjNw=; h=X-UI-Sender-Class:Date:From:To:Subject:References:In-Reply-To; b=KOWiDtUNtMCo8khdGkfaOFJR2MwXjE1JFkAdYZ4WY5u5n3ZmwcExe5wJ+YLTrpu0l eUIj9RkyxIqi7FdK/2tzyktS71ePjmmBH1qUi10jEqmzBm0vgBayp9oK5wVfJa64PK H2HD5iKZt2SY4uIbtWQhuTeIuSjK+F0eLcc67YC0= X-UI-Sender-Class: 01bb95c1-4bf8-414a-932a-4f6e2808ef9c Received: from scdbackup.webframe.org ([79.222.46.132]) by mail.gmx.com (mrgmx002 [212.227.17.190]) with ESMTPSA (Nemesis) id 0MOx4J-1hJml328Kl-006Plo for ; Fri, 10 May 2019 09:11:06 +0200 Date: Fri, 10 May 2019 09:09:25 +0200 From: "Thomas Schmitt" To: grub-devel@gnu.org Subject: Re: grub-mkrescue: Problem with MBR partition table at start of EFI partition Content-Type: text/plain; charset="utf-8" References: <9287678441821258435@scdbackup.webframe.org> In-Reply-To: <9287678441821258435@scdbackup.webframe.org> Message-Id: <8780678430873998037@scdbackup.webframe.org> X-Provags-ID: V03:K1:QF3QXxWJxdZkhKKWI1I/d7i/TilDAoXXpTc7zs5tFSKYWFGVR1i ka9ahteZiqQZS+PYYmwIvs6/zDlFdTfLG5JPypQreOf5C4uOr26gTaLjkzOUBNqjnquq5G/ AY2BhezJorfnPqL/US7sM4hhNrj5X2TWn9U3wgugAHAxpafOGwA0ZSRNN5G+cYAmoRdLtYQ muhkm4gdYH56USBS5Nb4Q== X-UI-Out-Filterresults: notjunk:1;V03:K0:byxkwVwrJds=:zJNPPV04a9YOipu2avBKyK aprzN6VjoG45OSTrlZr4y8xakLm/nj60KAsJEp+ir+geC87ylXwOG+v7odsireHqPh12xfdvH SEdmdDeED3ahDdv/OWHRK/F40eON0Vyhoopf8Znr3C/1D48HL5DD0dDKm+A2XJypqRlCa/lff wvXb/CiHhZMgbZUrewswaglxhG1yvjZYu6w08r/nVAzyCjI3xn+2mdK/M0gpevnBuPLL3K03A gVv/BaWsM5cJ8gTiikP0tY8zpHl6ibN+V4QL9RE2C0egYRokUDcgfJ98AI2mK48LU6rtNCokB KBy5MaLbD5YAWGa+z8cMyPtHZcsuwFfDW2fTxzJJHw/nqBSR0yeK/5LZo3ZJra8xLLMe8XDmQ oyOVirI1NnxAhYuJFg3JAcudcjT/Pjjl70RElynUBq8L+ZHlR56MHWmJij46l4zxMIrvRnb8Q rDnAXYEfJK9jU0t71XnGQ7jn5DqCOgTm2i8Pnnioh5cWAwFPnWIlCtK3Qq5Imdq5xlmDre/Kr YoEk+8nm9Cn616rxig+hrkSqJTQOZW2eQ3yF/mPS4Sg2ukI7yeSH1e2SqolwSObw/ced+uyOL NhCE6VSn4XqnUpzY8nH0qt3SjRjzRtiucNnd0gB6o0zsb6acfiI3+cnAoK2zUMamoJTf+3Yfh H88vhXkNqHwodw9jjZqf1eAkpozNFIf1DpRlDpIEAqsNj00MRvcINpwNIaMUGuB3rysTmxFar dULYAUhUT0SdHmbQqfx/iZbJpSmixTGs+2A5TEYjoFqlwP374SLIVDJPjzaBA+hFvZmtO1q0V THHibhVH9YFz0TPTdL1eXm6T4dITJFSbDWPhUeXafExYTx6tr1l/BBWTh7c6Gc2uVwSbuu5Wj 5XfvDU80Gx7GvGkgA6yjj+8/F/zzcS6tFdeq6IWYb/0Rw80ORWhwcs+9GZI2NFDz/vzBK3TjA OFVG2z7T5Kw== X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 212.227.15.19 X-BeenThere: grub-devel@gnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: The development of GNU GRUB List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 10 May 2019 07:11:10 -0000 Hi, iwrote: > What do you get as hex dump of byte 1,062,912 to 1,063,423 ? I found the answer in the hex dump: 00103800 eb 3c 90 4d 53 44 4f 53 35 2e 30 00 02 01 01 00 |.<.MSDOS5.0.....| 00103810 02 e0 00 40 0b f0 09 00 12 00 02 00 00 00 00 00 |...@............| 00103820 00 00 00 00 00 00 29 c0 56 ef 00 45 46 49 53 45 |......).V..EFISE| 00103830 43 54 4f 52 20 20 46 41 54 31 32 20 20 20 fa 33 |CTOR FAT12 .3| 00103840 c0 8e d0 bc 00 7c 16 07 bb 78 00 36 c5 37 1e 56 |.....|...x.6.7.V| 00103850 16 53 bf 3e 7c b9 0b 00 fc f3 a4 06 1f c6 45 fe |.S.>|.........E.| 00103860 0f 8b 0e 18 7c 88 4d f9 89 47 02 c7 07 3e 7c fb |....|.M..G...>|.| 00103870 cd 13 72 79 33 c0 39 06 13 7c 74 08 8b 0e 13 7c |..ry3.9..|t....|| 00103880 89 0e 20 7c a0 10 7c f7 26 16 7c 03 06 1c 7c 13 |.. |..|.&.|...|.| 00103890 16 1e 7c 03 06 0e 7c 83 d2 00 a3 50 7c 89 16 52 |..|...|....P|..R| 001038a0 7c a3 49 7c 89 16 4b 7c b8 20 00 f7 26 11 7c 8b ||.I|..K|. ..&.|.| 001038b0 1e 0b 7c 03 c3 48 f7 f3 01 06 49 7c 83 16 4b 7c |..|..H....I|..K|| 001038c0 00 bb 00 05 8b 16 52 7c a1 50 7c e8 92 00 72 1d |......R|.P|...r.| 001038d0 b0 01 e8 ac 00 72 16 8b fb b9 0b 00 be e6 7d f3 |.....r........}.| 001038e0 a6 75 0a 8d 7f 20 b9 0b 00 f3 a6 74 18 be 9e 7d |.u... .....t...}| 001038f0 e8 5f 00 33 c0 cd 16 5e 1f 8f 04 8f 44 02 cd 19 |._.3...^....D...| 00103900 58 58 58 eb e8 8b 47 1a 48 48 8a 1e 0d 7c 32 ff |XXX...G.HH...|2.| 00103910 f7 e3 03 06 49 7c 13 16 4b 7c bb 00 07 b9 03 00 |....I|..K|......| 00103920 50 52 51 e8 3a 00 72 d8 b0 01 e8 54 00 59 5a 58 |PRQ.:.r....T.YZX| 00103930 72 bb 05 01 00 83 d2 00 03 1e 0b 7c e2 e2 8a 2e |r..........|....| 00103940 15 7c 8a 16 24 7c 8b 1e 49 7c a1 4b 7c ea 00 00 |.|..$|..I|.K|...| 00103950 70 00 ac 0a c0 74 29 b4 0e bb 07 00 cd 10 eb f2 |p....t).........| 00103960 3b 16 18 7c 73 19 f7 36 18 7c fe c2 88 16 4f 7c |;..|s..6.|....O|| 00103970 33 d2 f7 36 1a 7c 88 16 25 7c a3 4d 7c f8 c3 f9 |3..6.|..%|.M|...| 00103980 c3 b4 02 8b 16 4d 7c b1 06 d2 e6 0a 36 4f 7c 8b |.....M|.....6O|.| 00103990 ca 86 e9 8a 16 24 7c 8a 36 25 7c cd 13 c3 0d 0a |.....$|.6%|.....| 001039a0 4e 6f 6e 2d 53 79 73 74 65 6d 20 64 69 73 6b 20 |Non-System disk | 001039b0 6f 72 20 64 69 73 6b 20 65 72 72 6f 72 0d 0a 52 |or disk error..R| 001039c0 65 70 6c 61 63 65 20 61 6e 64 20 70 72 65 73 73 |eplace and press| 001039d0 20 61 6e 79 20 6b 65 79 20 77 68 65 6e 20 72 65 | any key when re| 001039e0 61 64 79 0d 0a 00 49 4f 20 20 20 20 20 20 53 59 |ady...IO SY| 001039f0 53 4d 53 44 4f 53 20 20 20 53 59 53 00 00 55 aa |SMSDOS SYS..U.| An MBR signature 55 aa. But cleartext where the partition table should be. If Microsoft ISOs shall really be considered standard, then any kind of garbage is ok in a potential partition table at the start of the EFI partition. The firmware of the affected Macbook probably tolerates everything except four zeros at byte offset 454 (here: 0x1039c6), where Microsoft has 20 61 6e 64. (It feels like two cars speeding on a salt lake. Probability for collision is low. Just close your eyes and trust in your luck.) Have a nice day :) Thomas