Задача: загрузить виртуальную машину с USB устройства
Исходные данные:
хоcт ПК ОС: Mageia 4 (Linux mypc.mydrafts.local 3.12.8-desktop-2.mga4 #1 SMP Fri Jan 24 13:56:55 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux)
VirtualBox: 4.3.6_OSEr91406
флешка 1 /dev/sdd: Multiboot Flash Filth Edition 2013 + UEFI 7.1 Final 32 Гб 😉
флешка 2 /dev/sdf: MS DOS 6.22
Подключить и “найти” USB-устройство

# dmesg
[12533.059648] usb 7-6.1: new high-speed USB device number 4 using ehci-pci
[12533.142026] usb 7-6.1: New USB device found, idVendor=8564, idProduct=1000
[12533.142031] usb 7-6.1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[12533.142034] usb 7-6.1: Product: Mass Storage Device
[12533.142037] usb 7-6.1: Manufacturer: JetFlash
[12533.142039] usb 7-6.1: SerialNumber: DQ6M9ZTZ
[12533.192798] usb-storage 7-6.1:1.0: USB Mass Storage device detected
[12533.192841] scsi6 : usb-storage 7-6.1:1.0
[12533.192890] usbcore: registered new interface driver usb-storage
[12534.195883] scsi 6:0:0:0: Direct-Access JetFlash Transcend 64GB 8.07 PQ: 0 ANSI: 2
[12534.197664] sd 6:0:0:0: [sdd] 125493248 512-byte logical blocks: (64.2 GB/59.8 GiB)
[12534.198420] sd 6:0:0:0: [sdd] Write Protect is off
[12534.198425] sd 6:0:0:0: [sdd] Mode Sense: 03 00 00 00
[12534.199114] sd 6:0:0:0: [sdd] No Caching mode page found
[12534.199119] sd 6:0:0:0: [sdd] Assuming drive cache: write through
[12534.202160] sd 6:0:0:0: [sdd] No Caching mode page found
[12534.202166] sd 6:0:0:0: [sdd] Assuming drive cache: write through
[12534.203769] sdd: sdd1
[12534.207542] sd 6:0:0:0: [sdd] No Caching mode page found
[12534.207546] sd 6:0:0:0: [sdd] Assuming drive cache: write through
[12534.207549] sd 6:0:0:0: [sdd] Attached SCSI removable disk
...
...
...
[15636.465604] usb 7-6.6: new full-speed USB device number 8 using ehci-pci
[15636.541002] usb 7-6.6: New USB device found, idVendor=04e8, idProduct=0100
[15636.541008] usb 7-6.6: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[15636.541011] usb 7-6.6: Product: USB DRIVE
[15636.541013] usb 7-6.6: Manufacturer:
[15636.541016] usb 7-6.6: SerialNumber: 0187126789574
[15636.541497] usb-storage 7-6.6:1.0: USB Mass Storage device detected
[15636.541555] scsi10 : usb-storage 7-6.6:1.0
[15637.545245] scsi 10:0:0:0: Direct-Access USB DRIVE 1.12 PQ: 0 ANSI: 1 CCS
[15637.546119] sd 10:0:0:0: [sdf] 503808 512-byte logical blocks: (257 MB/246 MiB)
[15637.549212] sd 10:0:0:0: [sdf] Write Protect is off
[15637.549217] sd 10:0:0:0: [sdf] Mode Sense: 23 00 00 00
[15637.552353] sd 10:0:0:0: [sdf] No Caching mode page found
[15637.552358] sd 10:0:0:0: [sdf] Assuming drive cache: write through
[15637.560372] sd 10:0:0:0: [sdf] No Caching mode page found
[15637.560377] sd 10:0:0:0: [sdf] Assuming drive cache: write through
[15637.566380] sdf: sdf1
[15637.580415] sd 10:0:0:0: [sdf] No Caching mode page found
[15637.580420] sd 10:0:0:0: [sdf] Assuming drive cache: write through
[15637.580424] sd 10:0:0:0: [sdf] Attached SCSI removable disk

Изменить права
под рутом:

# chmod 666 /dev/sdf
# chmod 666 /dev/sdd

Создать VMDK-диск для ВМ

# VBoxManage internalcommands createrawvmdk --help
Oracle VM VirtualBox Command Line Management Interface Version 4.3.6_OSE
(C) 2005-2013 Oracle Corporation
All rights reserved.Usage: VBoxManage internalcommands  [command arguments]Commands:createrawvmdk -filename -rawdisk
[-partitions [-mbr ] ]
[-relative]
Creates a new VMDK image which gives access to an entite host disk (if
the parameter -partitions is not specified) or some partitions of a
host disk. If access to individual partitions is granted, then the
parameter -mbr can be used to specify an alternative MBR to be used
(the partitioning information in the MBR file is ignored).
The diskname is on Linux e.g. /dev/sda, and on Windows e.g.
\\.\PhysicalDrive0).
On Linux or FreeBSD host the parameter -relative causes a VMDK file to
be created which refers to individual partitions instead to the entire
disk.
The necessary partition numbers can be queried with
VBoxManage internalcommands listpartitions

WARNING: This is a development tool and shall only be used to analyse
problems. It is completely unsupported and will change in
incompatible ways without warning.

Syntax error: Invalid parameter '--help'

# VBoxManage internalcommands createrawvmdk -filename /home/mydrafts/VirtualBox\ VMs/tmp/msdossdf.vmdk -rawdisk /dev/sdf
# VBoxManage internalcommands createrawvmdk -filename /home/mydrafts/VirtualBox\ VMs/tmp/sysadminkey64gbUSB2sdd.vmdk -rawdisk /dev/sdd

Подключить к виртуальной машине:
Multiboot Flash Filth Edition 2013 + UEFI 7.1 Final 32 Гб -> /dev/sdd -> sysadminkey64gbUSB2sdd.vmdk

MS DOS 6.22 -> /dev/sdf -> msdossdf.vmdk

Загрузиться
При таком раскладе, надо во время загрузки нажать F12

далее нажать:
1 — что бы загрузить “флешку” с Multiboot Flash Filth Edition 2013 + UEFI 7.1 Final 32 Гб;

2 — MS DOS 6.22