From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Thomas Schmitt" Subject: Re: ISO installer image: GPT versus MBR partitions Date: Sat, 20 Apr 2019 13:16:14 +0200 Message-ID: <32128673174594726028@scdbackup.webframe.org> References: <28973673174197768455@scdbackup.webframe.org> Content-Type: text/plain; charset="utf-8" Return-path: Received: from eggs.gnu.org ([209.51.188.92]:45950) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hHny6-0000OU-Ta for guix-devel@gnu.org; Sat, 20 Apr 2019 07:15:39 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hHnwa-00085w-CD for guix-devel@gnu.org; Sat, 20 Apr 2019 07:14:05 -0400 In-Reply-To: <28973673174197768455@scdbackup.webframe.org> 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 now look at the FAT filesystem images of Debian Live 9 and Guix 0.16.0: Guix: - There is an MBR partition table in the image file: Device Boot Start End Sectors Size Id Type /mnt/iso/efi.img1 * 0 2879 2880 1.4M 1 FAT12 - Program "file" says: DOS/MBR boot sector, code offset 0x3c+2, OEM-ID "MTOO4021", root entries 224, sectors 2880 (volumes <=32 MB) , sectors/FAT 9, sectors/track 18, serial number 0x336648a7, unlabeled, FAT (12 bit), followed by FAT Debian: - No partition table in image. - Program "file" says: DOS/MBR boot sector, code offset 0x3c+2, OEM-ID "mkfs.fat", sectors/cluster 4, root entries 512, sectors 832 (volumes <=32 MB) , Media descriptor 0xf8, sectors/FAT 1, sectors/track 32, heads 64, serial number 0x64c6c435, unlabeled, FAT (12 bit) --------------------------------------------------------------------- My favorite suspect would be the partition table in Guix /efi.img. To kill table entry 1 after having put the Guix EFI image back into partition 2 of the USB stick: dd if=/dev/zero bs=1 count=16 seek=446 of=/dev/sdc1 --------------------------------------------------------------------- If this does not help, then create a new empty FAT filesystem image, mount it, and copy the tree from the mounted Guix /efi.img into it. The new filesystem should have between 200 KiB and 1.4 MiB. (The Guix image of 1.4 MiB still has 90 % of its capacity free.) Then put the new filesystem into /dev/sdc2 and see what happens. --------------------------------------------------------------------- If this does not help, then copy again the Debian efi.img into partition 2, mount it, and replace the file bootx64.efi by the one of the mounted Guix efi.img. --------------------------------------------------------------------- Have a nice day :) Thomas