Hi, shirish wrote: > https://cdimage.debian.org/cdimage/buster_di_alpha2/amd64/iso-cd/debian-buster-DI-alpha2-amd64-xfce-CD-1.iso
Just to be sure that no regression confuses us here, i downloaded that ISO and let xorriso analyse its boot equipment: xorriso -indev debian-buster-DI-alpha2-amd64-xfce-CD-1.iso \ -report_el_torito plain -report_system_area plain reports El Torito images : N Pltf B Emul Ld_seg Hdpt Ldsiz LBA El Torito boot img : 1 BIOS y none 0x0000 0x00 4 2011 El Torito boot img : 2 UEFI y none 0x0000 0x00 832 1803 So it can boot from DVD via BIOS and via EFI firmware. System area summary: MBR isohybrid cyl-align-on GPT APM The presence of word "isohybrid" in this line indicates that it can boot from USB stick via BIOS. The x86 program code in the Master Boot Record will transfer program execution to the El Torito boot image for BIOS. MBR partition table: N Status Type Start Blocks MBR partition : 1 0x80 0x00 0 1327104 MBR partition : 2 0x00 0xef 7212 832 The presence of an MBR partition of type 0xef indicates that it can boot from USB stick via EFI firmware. The partition table entry marks a range in the ISO image where a FAT filesystem exists with file /EFI/BOOT/BOOTX64.EFI which EFI will execute as x86 EFI program. (32-bit x86 EFI expects and runs /EFI/BOOT/BOOTIA32.EFI.) So yes, this ISO should boot after being put plainly onto an USB stick and then offered to BIOS or EFI as boot device. After booting, /dev/sdX and /dev/sdX1 are both mountable as the ISO 9660 filesystem with nearly all the beef. /dev/sdX2 should be mountable as FAT filesystem with just the two directories and the one file BOOTX64.EFI. ("X" is the device number which depends on the presence of other devices.) > I will definitely try rufus in dd mode but as of buy the sticks, make > sure they are genuine I'd make that quality check on a GNU/Linux system, where one can rely that dd does no things that are smarter than wanted: dd if=debian-buster-DI-alpha2-amd64-xfce-CD-1.iso bs=1M of=/dev/sdX Use script check_debian_iso to verify that all written bytes are correctly readable. Then overwite the USB stick with zeros dd if=/dev/zero bs=1M count=650 of=/dev/sdX in order to erase the successfully copied ISO. This verified and then wiped USB stick would be a reliable test bed for Rufus et.al. If you finally have success, please provide a short description which menus or buttons of Rufus need to be used for getting it into DD mode. Have a nice day :) Thomas