Note: You can make a 'partition image' file of any Vista/7/8/10 Windows Installer ISO using MakePartImage - then you won't need to use a 'Helper' Flash drive. See here for more details.
How to make a 'Helper' USB Flash Drive for Windows .ISO payload files
'A required CD/DVD drive device driver is missing.'
If you have an E2B USBHard disk or you have an E2B USB Flash drive of the 'Fixed Disk'/'Local Disk' type (as shown by RMPrepUSB or Windows Explorer), then some WinPE .ISOs and all Vista, Win7, SVR2K8, SVR2012 and Win8 Windows Install ISOs and WinPE ISOs will not work correctly because you will not get the blue console window (see below) which runs ImDisk and loads the ISO as a virtual DVD.
It may be helpful to you, if you understand how E2B works and why E2B needs to have a Removable USB drive to get Windows Install ISOs to work - see here and look for the 'Windows Install ISOs' section, for the details.
Tip: If you have an IODD 2531 or 2541, unzip \_ISO\docs\USB FLASH DRIVE HELPER FILES\E2B_WinHelper_&DW.zip and simply load the \_ISO\docs\USB FLASH DRIVE HELPER FILES\E2B_WinHelper_&DW.RMD file as a virtual drive using the jog wheel. This will then emulate a Removable WinHelper Flash drive. The E2B_WinHelper_&DW.RMD file can be placed in the \_ISO folder for quicker access.
To fix the 'device driver is missing' issue, you need to make an extra USB Flash 'Helper' drive as follows.
1. You need an additional small (any size) USB Flash drive that is of the 'Removable' type - check it is of the correct type using RMPrepUSB, or make sure that it is not listed in Windows Explorer as a 'Local Disk'. It can be any size as it only needs to hold a few files. It does not matter if your other files are already on this drive. It does not need to be re-formatted if it is already formatted as either FAT32 or NTFS.
2. Ensure this Helper USB drive does NOT contain the E2B files (i.e. it does not contain the \_ISO\e2b folder).
3. Copy the files from the E2B folder \_ISO\docs\USB FLASH DRIVE HELPER FILES folder to the root of the USB Helper drive. Ensure that you copy the files to the first partition of the Removable USB Flash drive (usually there is only one partition accessible in Windows anyway). \WINHELPER.USB, \Autounattend.xml and \unattend.xml should now be present in the root of the Helper Flash drive. Do NOT edit these files. They will be changed by E2B.
Now whenever you boot from the E2B USB Hard disk to install Windows Vista/7/8, be sure to also connect this USB E2B Helper drive too (it is only needed if booting some Windows-based ISOs - e.g. Windows Vista/7/8 Install ISOs and some PE-based ISOs which need to access the 'CD' after they boot).
USB Port 1: E2B 'Fixed Disk'-type drive containing E2B files
USB Port 2: 'Helper' Removable Drive'-type Flash drive containing 'Helper' files.
If Helper files are found in the root of a drive by E2B, you should see a message similar to that above, just before the E2B Main Menu is displayed.
IMPORTANT: Only one drive in the entire system must contain the E2B files - do not put all the E2B files and folders on the Helper USB drive! Also, only one drive in the whole system must contain the \WINHELPER.USB file.
If possible, use USB 2.0 ports and not USB 3.0 ports, because Windows Vista and 7 does not contain USB 3.0 drivers and so Windows Setup won't detect the USB Helper drive.
Note: If you convert the Windows ISO to a .imgPTN file, then you don't need to use a Helper Flash drive.
Troubleshooting Installing Windows using an E2B USB Helper flash drive
1. Ensure that the USB Helper flash drive is of the 'Removable' type (ensure it appears as a Removable Disk in Windows Explorer and in RMPrepUSB - see screenshot above)
2. Check that it is detected by your BIOS - you should be able to see it listed by the BIOS boot selection menu - if not try using different USB ports and try formatting it using RMPrepUSB as FAT32+Boot as HDD options. If possible, always use the BIOS Boot Selection (BBS) menu (e.g. press F10 or F12) rather than set the boot order in the BIOS Boot-order menu.
3. You must install using a real system - running under a VM or Emulator will not work because the USB Flash drive will be detected as a 'Fixed Disk'.
4. Use a mainboard USB port that the BIOS can detect - if you have an add-in USB 3.0 PCI card, don't connect any USB drives to those ports.
5. If you are using a USB 3.0 port that is detected by the BIOS, then Vista and Win7 Installs won't work because those OS's don't contain USB 3.0 drivers - use USB 2.0 ports only for pre-Win8 OS's. Some USB 2.0 ports in modern systems are not recognised by Vista/Win7. In this case you will need to add USB 2.0 or 3.0 drivers into the ISO.
6. Check that E2B has detected the Helper Flash drive - you should see an E2B progress message just before the Main menu is displayed 'Wiping /AutoUnattend.xml and /Unattend.xml files on WINHELPER.USB...'. Also the Helper drive LED should flash for about a second at this point. You should also see the Helper LED flash just before E2B boots from the Windows Install ISO file after the 'booting...' message.
7. If the Windows blue 'LOAD WINDOWS ISO USING IMDISK' console window did not appear before you get to the first Windows Install Setup screen (e.g. choose Country, etc.), press SHIFT+F10 to open a Windows console. Type NotePad and then open the \AutoUnattend.xml file on the Helper Flash drive with NotePad - it should contain lots of xml text. If not, it was not updated by E2B (probably because it was not detected by the BIOS)
This 'blue console window' loads the ISO file as a virtual DVD - it MUST run so that Setup will 'see' a DVD drive.
8. Follow the instructions below to manually run LOADISO.CMD and get the blue console window.
Making it work without needing a Helper Flash drive
1. Boot to E2B and start the Windows ISO boot
2. As soon as Setup loads and asks you for a language/country, press the key combination SHIFT+F10- a black console window should open (if SHIFT+F10 does not work, answer the next question and try SHIFT+F10 again)
3. In the console window, type dir C:\_ISO and press the ENTER key - if the folder is not listed, try dir D:\_ISO etc. until you find the E2B USB drive letter - let us assume that 'dir E:\_ISO' worked - then the USB drive letter must be E:
4. Now run loadiso by typing E:\_ISO\e2b\firadisk\loadiso.cmd - the blue console window should open - if then prompted to Repair Windows, just hit ENTER
5. The blue console Window should close - now continue with Windows Setup in the normal way.
Note: You can place the E2B files and payload files on any partition on a USB HDD (or USB Flash drive that is of the 'Fixed Disk' type) but if using a Removable-type of USB Flash drive, the first partition should contain E2B and the Windows Install ISOs.
New: You can make a 'partition image' file from any Vista/7/8 Windows Installer ISO file using MakePartImage - then you won't need to use a 'Helper' Flash drive and can also do UEFI-boot installs. See here for more details.
Make the Helper drive bootable (not recommended)
You can also make the Helper Flash drive bootable, so that you can boot from either the E2B Hard disk or the E2B Helper flash drive, as follows:
1. Using RMPrepUSB, install grub4dos using the Install Grub4dos button - I suggest installing to the MBR and PBR. Ensure that the \grldr file is copied to the E2B Helper drive.
2. Press F4 in RMPrepUSB and add the following contents to the new \menu.lst file - save it and exit Notepad (this is already present in later versions of E2B).
pause --wait=3 Booting from Easy2Boot USB Helper Flash Drive...
find --set-root /_ISO/e2b/grub/menu.lst
You can now boot from the Helper drive and it will then chainload (reboot) onto the E2B USB Hard drive.
The 'helper' files must be on the first partition of the USB Flash drive so that they can be seen by Windows.
Note: When you boot from a Helper USB Flash drive, not all E2B payloads will work because the E2B USB drive will not be (hd0).