USB boot creation

YUMI

YUMI (Your Universal Multiboot Integrator), is the successor to our MultibootISOs. It can be used to create a Multiboot USB Flash Drive containing multiple operating systems, antivirus utilities, disc cloning, diagnostic tools, and more. Contrary to MultiBootISOs which used grub to boot ISO files directly from USB, YUMI uses syslinux to boot extracted distributions stored on the USB device, and reverts to using grub to Boot Multiple ISO files from USB, if necessary.

Creation / reinitialisation d'une clef bootable à partir d'une image iso

Pour images iso créées avec isohybrid (dont centos, rhel) on créé la cle USB bootable directement à partir de l'image iso avec une copie dd, par exemple:

 # dd if=rhel-server-7.8-x86_64-dvd.iso of=/dev/sdx bs=512k

Ensuite, une fois l'installation effectuée, on réinitialisera la clef avec les étapes:

 # fdisk –l /dev/sdx
 Disk /dev/sdx: 7736 MB, 7736072192 bytes, 15109516 sectors
 Units = sectors of 1 * 512 = 512 bytes
 Sector size (logical/physical): 512 bytes / 512 bytes
 I/O size (minimum/optimal): 512 bytes / 512 bytes
 Disk label type: dos
 Disk identifier: 0x34588513
 Device     Boot  Start   End    Blocks  Id  System
 /dev/sdx1   *     0    3655679 1827840  0   Empty
 /dev/sdx2        1036  18711    8838    ef  EFI (FAT-12/16/32)

Ici, on va supprimer les partitions sdx1, sdx2 et en recréer une avec fdisk:

 # fdisk /dev/sdx
 Welcome to fdisk (util-linux 2.23.2).
 Changes will remain in memory only, until you decide to write them.
 Be careful before using the write command.
 Command (m for help): d
 Partition number (1,2, default 2):
 Partition 2 is deleted
 Command (m for help): d
 Selected partition 1
 Partition 1 is deleted
 Command (m for help): n
 Partition type: 
   p primary (0 primary, 0 extended, 4 free)
   e extended
 Select (default p):
 Using default response p
 Partition number (1-4, default 1):
 First sector (2048-15109515, default 2048):
 Using default value 2048
 Last sector, +sectors or +size{K,M,G} (2048-15109515, default 15109515):
 Using default value 15109515
 Partition 1 of type Linux and of size 7.2 GiB is set
 Command (m for help): t
 Selected partition 1
 Hex code (type L to list all codes): L
 0  Empty          24 NEC DOS           81 Minix / old Lin bf Solaris
 ...etc...
 b W95 FAT32       51 OnTrack DM6 Aux   9f BSD/OS          e4 SpeedStor
 c W95 FAT32 (LBA) 52 CP/M              a0 IBM Thinkpad hi eb BeOS fs
 ...etc...
 Hex code (type L to list all codes): c
 WARNING: If you have created or modified any DOS 6.xpartitions, please see the fdisk
 manual page for additionalinformation.
 Changed type of partition 'Linux' to 'W95 FAT32 (LBA)'
 Command (m for help): w
 The partition table has been altered!
 Calling ioctl() to re-read partition table.
 Syncing disks.

Puis formatter en vfat:

 # mkfs.vfat /dev/sdx1
 mkfs.fat 3.0.20 (12 Jun 2013)