Advantages and disadvantages of using .imgPTN files
Quick Start - how to make .imgPTN files
Introduction to .imgPTN files
How to use MakePartImage.cmd
MakePartImage user prompts
How does E2B boot to .imgPTN files?
Directly boot in UEFI mode with Clover
Modify the CSM menu
What does MakePartImage.cmd actually do?
New! 130-page PDF eBook (complete course on making a multiboot USB drive).
Please note: Once you 'switch-in' a .imgPTN file, it will replace the E2B partition and the E2B files will 'disappear'.
You then will have a 'different' drive volume present. Any changes you make to the files will be permanent, just like any normal drive volume and those changes will still be there the next time you switch to the same .imgPTN file.
To restore the original E2B partition and E2B files, you should MBR-boot and select Item #0 from the CSM Menu, or you can run the Windows utility \e2b\SWITCH_E2B.exe and click on Restore E2B Partition(s).
Advantages of using .imgPTN files
Can UEFI-boot (if payload supports it and use FAT32 .imgPTN) and MBR\CSM-boot
Can run any number of Windows, linux or other UEFI software (e.g. MemTest86, KonBoot, etc.)
Can run Windows installers from an E2B USB HDD (no removable flash drive required)
Can run All-In-One Windows installs
Best way to run multiple Hirens Boot CDs
Can run .imgPTN files from any menu folder
Can run Windows To Go
Can run multiple fully installed linux installations
Can run FreeBSD/PfSense/Hackintosh installers
Can run WinBuilder/WinPE (and UEFI-boot if payload supports it)
No UEFI-bootloader is used, so Secure Boot will work if the payload contains signed EFI boot files
If your USB drive has a write-protect switch, you can switch in a .imgPTN file first and then write-protect the drive before booting from it.
If your E2B USB drive has a second partition, they can be temporarily removed or can remain as a valid partition.
Disadvantages of using .imgPTN files
Must boot to E2B Menu first (in MBR\CSM mode) or run the Windows SWITCH_E2B.exe utility to 'switch-in' the new partition.
Download MemTest86.imgPTN - a ready-made payload
So that you can download and test an .imgPTN file quickly to see how to use one - go here.
Extract the MemTest86.imgPTN file and copy it to \_ISO\MAINMENU folder
Now you can either boot to the E2B menu and select the MemTest86 menu entry
- OR -
Run \_ISO\SWITCH_E2B.exe under Windows and double-click on the MemTest86.imgPTN file.
Now your E2B drive contains MemTest86 and can be MBR or UEFI-booted (or MBR-boot and run Clover if you have a non-UEFI BIOS).
Secure Boot is supported by MemTest86 too!
Tip: You can move the MemTest86.imgPTN file to any E2B menu folder (e.g. \_ISO\UTILITIES_MEMTEST) to place it in a different E2B menu. If you change the file extension to .imgPTNauto, E2B will switch-in the partition image without prompting you.
Quick Start Instructions - how to make .imgPTN files
1. Download and extract the MPI Tool Kit to your system hard disk
2. Install ImDisk from the ImDisk folder (WinRar is also recommended to be installed too - read the ReadMe file for details)
3. Double-click CreateDesktopShortcuts.cmd to create the 3 Desktop shortcut icons...
4. Drag-and-Drop an ISO (or USB drive icon, CD\DVD drive letter or any folder) onto the MPI_FAT32 Desktop icon to make a .imgPTN file (max. 32GB for FAT32).
If prompted, just hit [ENTER] to accept the default size (or if there is a size problem, increase the size until it fits).
Note: To avoid problems, do not use special characters in the folder name or the file name (e.g. do not use & or parentheses/brackets).
5. .imgPTN files must be contiguous. Double-click on the MAKE_THIS_DRIVE_CONTIGUOUS.cmd script in the root of the E2B USB drive:
Tip: If you use a file extension of .imgPTN23 then any second or third Primary partition on the E2B USB drive will NOT be removed when you switch in the new image file. This is useful if you wish to UEFI-boot and still have the files on a second partition of the E2B Hard Disk accessible. For instance, PortableApps or disk images can be kept on a second partition.
Note: If using a FAT32 .imgPTN file and there is a file larger than 4GB - see here for details on how to fix this.
Click here to watch a MakePartImage video and also here.
MakePartImage.cmd (MPI) is a Windows script that makes a partition image (.imgPTN file) from an ISO (or .zip file or drive or folder). MakePartImage creates a 'virtual drive' using ImDisk, copies the payload files into it and then copies the whole 'virtual drive' contents to a file called a 'partition image' file. E2B recognises a variety of partition image files that begin with the special file extension prefix '.imgPTN' (e.g. .imgPTN23,.imgPTNa, .imgPTNLBA, .imgPTNAUTO or .imgPTNLBAa, etc. - see here for a list).
For instance, MPI will make a .imgPTN file directly from a Windows Install or linux bootable LiveCD ISO file. You can then simply copy the .imgPTN file to your Easy2Boot (E2B) USB drive, select it and boot from it.
When you run any .imgPTNxxxx file from the Easy2Boot menu, it removes the Easy2Boot partitions on the USB drive and replaces them with the .imgPTN partition.
For instance, if you made a .imgPTN file from a Windows 8.1 installer ISO file, after you select that .imgPTN file from the E2B menu, your USB drive would then contain a single partition containing the files within that image (the Win8.1 files). E2B will display the CSM Menu which will allow you to boot to that OS or switch back to the original E2B menu by restoring the original E2B USB disk partition(s).
BEFORE - Two-partition E2B drive (blue square shows location of a 262MB .imgPTN file)
AFTER SWITCHING - USB drive now only contains 262MB FAT32 partition
Typically, you will add .imgPTN files to your Easy2boot USB drive to allow you to boot to Windows Installers, MSDaRT and Linux Live CDs in UEFI mode. .imgPTN files can be used for UEFI booting, but only if you ensure that FAT32 is used for the image format (i.e. the E2B drive can be formatted as NTFS when you make it, but when you make the image file using MPI, you must specify FAT32 for the image file format by using the MPI_FAT32 desktop shortcut).
.imgPTN files can also be used to boot Windows Install payloads in MBR\CSM mode from an E2B USB hard drive, but without needing the additional USB 'Helper' Removable Flash drive. For MBR\CSM booting the partition image file can be either FAT32 or NTFS.
You can add any number of .imgPTN files to your E2B USB drive and boot from any of them in normal BIOS MBR mode (and UEFI mode, if supported by the payload).
N.B. Some buggy UEFI systems will not offer the user a MBR\CSM boot option if there are UEFI boot files present on the USB drive. This means that after changing to an .imgPTN file which contains EFI boot files, you may not be able to boot to the CSM Menu and restore the drive back to the E2B menu. For these systems, you must either MBR-boot on a different system, or use a Windows system to run \e2b\SWITCH_E2B.exe to restore the E2B partitions.
You can also use MakePartImage to make an image file of your other favourite bootable USB Flash drives (e.g. YUMI, UUI, WinSetupFromUSB, Rufus, WindowsToGo, etc.) and simply add the .imgPTN file to your E2B drive.
Clover is a pseudo UEFI firmware-in-RAM replacement which is included in the MPI 'payload' and will be listed in the CSM Menu if EFI boot files are present.
Clover will allow you to boot to a UEFI OS from Easy2Boot without needing to reboot your system in UEFI mode.
E2B also supports dual partition images. The first partition image's file extension must start with .imgPTN (e.g. fred.imgPTNAUTO) and is mapped into the partition 1 position, the second image (if present) must be named identically but with no file extension and no dots in the name (e.g. fred) - this is mapped to partition 3 by E2B. Once you select the .imgPTN file in E2B, both partitions will be 'switched in'. Note that Windows will only be able to access the first paritition if the E2B USB drive is of the 'Removable' type though.
Tip: If some systems don't boot when in the CSM-mode (flashing cursor) then try a file extension of .imgPTN23. See FAQ
Frettt has provided a German translation of the CSM Menu.lst file - check the Alternate Downloads - Other files folder!
I strongly recommend that you read the MPI ReadMe.txt file first.
1. Download the MPI Tool Pack and then install ImDisk onto your Windows system (it is in the ImDisk folder in the download). Also install WinRAR (required when 7Zip cannot open some ISO files).
Recommended: If you are using Windows Vista\7\8, then you can automatically create Desktop shortcuts by double-clicking on the CreateDesktopShortcuts.cmd file.
About the MPI shortcuts: If you have spaces in the path for the 'Target' field, then we must use double-quotes for the part of the path after the drive letter - e.g.
cmd.exe /c F:\"temp\name with spaces\MakePartImage\MakePartImage.cmd"
This may seem 'wrong', but enlosing the whole path in double-quotes does not work!
2. Drag-and-Drop an ISO (or USB drive icon or folder) onto the MPI_FAT32 Desktop shortcut icon (or MPI_NTFS shortcut) to make a .imgPTN file.
I suggest that the source ISO file is NOT on a USB drive (for reasons of speed and reliabuility).
If prompted, just hit [ENTER] to accept the default size.
OR... Run MakePartImage in a Windows command console as Administrator or right-click on the MakePartImage file and select 'Run as administrator'.
If prompted for a SOURCE - enter the full path of your ISO (or USB drive or folder) - use the TAB key for auto-completion. If specifying a folder, the folder path should end with a \ - e.g. C:\temp\myiso\. Instead you can also drag-and-drop onto the MakePartImage Desktop shortcut. You will now be asked a series of questions (see below), usually you just need to press the [Enter] key and the correct default choice will be made by MakePartImage.
If it fails to copy all the files, due to lack of space, run it again and increase the size of the image slightly, when prompted.
Note: When a folder is the source, make sure your .imgPTN file is not created in, or under, the same SOURCE folder or the operation will fail!
Tip: If 7Zip has problems unpacking the ISO files, try a different program (e.g. IsoBuster) and extract the contents of the ISO file to an empty folder. Then drag-and-drop the folder onto one of the MPI Desktop shortcuts.
Note: If your payload boots using syslinux/isolinux, you will need to choose which version of syslinux to install - hints are provided.
3. Once the .imgPTN image file is made, copy it to the \_ISO\MAINMENU folder of your E2B drive (or any other menu folder except \_ISO\WINDOWS or \_ISO\WINDOWS\XP).
Note: For other possible variants of .imgPTN file extensions, see here.
4. Run WinContig (\MAKE_THIS_DRIVE_CONTIGUOUS.cmd) on the E2B USB drive to ensure all the files are contiguous (or use RMPrepUSB - Ctrl+F2).
You can use the command line to convert an ISO using the suggested defaults and avoid a few key presses, by using the command line format:
MakePartImage f:\temp\mytest.iso * FAT32 1000
This will make a new image file with the same name and in the same folder as the source ISO, but with a .imgPTN extension and will use 1000MB for the size of the image file. For faster conversion, use a fast disk drive (preferably an SSD drive) as the target drive and then copy the .imgPTN file to your E2B USB drive.
Usage examples for MakePartImage
You can also drag-and-drop an ISO file onto a shortcut of MakePartImage and enter in all parameters manually.
Windows Explorer is launched at the end of running MakePartImage.cmd so you can copy the image file to your E2B drive.
To prevent Explorer from being run, first type
in the Windows command console (as Admin) before you run MakePartImage.cmd from the same console window.
Use a file extension of .imgPTNAUTO to suppress the E2B warning messages and immediately switch to the partition image and CSM menu when selected by the user.
MakePartImage.cmd (MPI) user prompts
Some of these questions may not appear, it depends on what command line parameters you have used and what source you specify. Default answers are indicated in square brackets by MakePartImage, usually you just need to press [Enter] to use the default answer.
Source ISO or Folder - specify either a path to an ISO file (or zip/7z file) (e.g. C:\fred\debian.iso) OR a USB drive that you want to 'clone' (e.g. G:\) or a folder that contains a copy of the source files (e.g. C:\temp\ExtractedWin8\). Note that the path should always end in a backslash. Remember, you can type TAB on the command line during typing, to make Windows complete the path or filename for you.
Use FAT32 for the new image (N=NTFS) (A/[Y]/N) : - Type either FAT32 or NTFS or hit enter for the default which is indicated by the [square brackets] (Y=FAT32 is the default). If you are using a Windows ISO which has a file >4GB inside it, you must choose NTFS (but it won't UEFI boot) or split the install.wim into smaller files - see here for details.
Size for Image file (MB), min=38 - e.g.  : - Enter the size that will be required for the partition image. Hit [Enter] for the suggested size (which is usually a tad generous). If the process fails due to insufficient space, run MPI again and increase the size.
OUTPUT FILENAME for new Image (e.g. C:\temp\xxx.imgPTN) : - A DEFAULT path and name may be suggested - if so, just hit [Enter], otherwise type a valid path and filename. If the path contains spaces, enclose the whole path in double-quotes. Usually E2B will require a .imgPTN file extension.
VOLUME NAME for partition [LIVE] : - MPI will use 'LIVE' as the default volume name OR if using a USB drive as the source, it will use the same Volume Name as the source USB drive. If the image is made from an XBOOT drive, use the Volume Name of XBOOT. Max = 11. Avoid using spaces. If the source is a folder, you will be prompted for a Volume name.
EI.CFG - if a Windows install payload is detected, you may be asked if you want to delete or make an EI.cfg file. This can enable more choices as often Windows Install ISOs contain multiple versions. If you are unsure what to answer - just press [Enter].
Windows 8/10 ISOs usually do not contain an EI.CFG file - if you add one it will allow you to pick any version contained inside the ISO. It will also avoid you having to enter a Product Key and also allow you to use 'split wim' files (.swm files).
If your source is a Windows 7 ISO, it usually contains an EI.CFG file - by using a modified EI.CFG file, you will be able to choose any version inside the ISO.
Which version of Syslinux shall I use (37,38,,5,6,N=None) : - Normally it is safe to use the suggested version. Some versions of linux may require Version 6 (tip: if you see a 'COM32R' error when booting from the CSM menu, then try '6' instead).
Press a key to dismount - At this point you can inspect and change the contents of the ImDisk RAM drive volume (usually U:). Once you press a key, the volume will be dismounted and all contents saved to the image file.
MENU.LST FOUND - OK to combine them ([Y]/R/N) : - If a menu.lst file is found, it indicates that the source payload is grub4dos bootable. As MPI installs it's own menu.lst file there is a problem! Normally the safest thing to do is combine the two menus, however you may find that some of the menu entries are redundant or don't work. If the main CSM 'Boot from this drive' entry works, then re-make the .imgPTN file and answer R for Replace. You are strongly advised to NOT answer N because unless you use the MPI CSM menu.lst, you will not be able to easily restore the E2B drive partitions after switching to the .imgPTN partition (but see the RestoreE2B utility below). Unless the menu contains the correct commands, E2B will refuse to run the .imgPTN file.
Title of the CSM menu : - If you did not use an ISO file as the source, then we need to know what the payload actually is, so we can display the name at the top of the CSM menu. You can edit this heading in the menu.lst file once the image is made.
INFORMATION: xxx occurs in the .YYY files - AUTO-CORRECT these? ([Y]/N) : - If syslinux, grub, EFI config files or isolinux files have been detected (.cfg, .lst or .conf) then MPI can attempt to do 'fixups' on these so that it matches the Volume Label of the partition and the UUID of the partition, as well as change the parameters for USB booting rather than CDROM booting. Normally, just hit [Enter] to change all these automatically. For a Hirens ISO, you may need to answer No to ensure any linux files still boot.
Tip: To see what it finds and what it changes them to, type set NOISY=1 at the command console before you run MPI.
WARNING: Cannot dismount volume U: - This is quite common/normal on some systems if you have Explorer windows open, hit [Enter] and another attempt will be made to dismount the ramdrive.
A Windows Explorer window will open if the image file was made successfully. If there was a problem the console background will change to a red colour and the ImDisk Manager Control Panel application may appear so that you can 'Remove' any ramdisk drive that is 'stuck'.
How does E2B boot to .imgPTN files?
When you boot from an E2B USB drive and you choose a .imgPTN file from the menu, E2B first backs up it's current MBR partition sector to sector LBA 30 or 60 (if unused) on the E2B drive.
Then E2B will erase all four partition table entries in the MBR and replace them with just one partition entry pointing to the start of the .imgPTN file that you have chosen.
If a filename of exactly the same name as the .imgPTN file exists (but has no file extension), it will also be automatically mapped at the 3rd partition of the partition table
The image will have a grub4dos menu.lst file and the grldr file so that you can boot from the new partition using the grub4dos MBR code that is still present on the E2B drive even after switching partitions.
In the partition image menu (CSM menu), there is a menu entry which will restore the original E2B MBR (it copies the sector at LBA 30/60 back to the MBR) - this allows you to return the USB drive back to it's original E2B partitions and file contents.
If the first partition (the image inside the .imgPTN file) is a FAT32 partition and the payload files within it support UEFI booting, you can reboot your computer and choose the 'UEFI: XXXX USB Boot' option from the system's BIOS/UEFI boot menu - the USB drive should then boot in UEFI-mode.
To return the drive back to it's original E2B state, boot it in CSM\MBR mode and choose the menu option to restore E2B and switch back to E2B mode.
Tip: You can test UEFI booting using VirtualBox+DavidB's VMUB utility from reboot.pro.
If Clover is included in your MPI folder, the image file made by it will also contain Clover and will be capable of booting UEFI payloads directly, without needing to reboot first and choose a UEFI boot option.
Tip: You can pre-select any .imgPTN file first, before you connect the E2B drive to the target UEFI system, by using QEMU_MENU_TEST (run as admin).cmd, RMPrepUSB+QEMU (F11), MobaLiveCD.exe or Virtual Box to select and switch in the new image to get to the CSM menu. You can also restore the E2B partitions(s) in the same way.
New! SWITCH_E2B is a Windows 32-bit application that allows you to select any .imgPTN file from Windows or return the drive to 'E2B' mode.
This is the CSM Menu - when you see this menu you are in MBR boot mode but the E2B partition has been replaced by your .imgPTN file.
You should see this CSM (MBR-Mode) menu when you MBR\CSM boot from a .imgPTN partition but you will not see this menu if booting via UEFI because it boots directly from a \EFI\boot\bootxxx.efi file.
Note that you can also boot directly to UEFI boot files by using the Clover menu entry (3). The payload's efi boot files that are present in the image, are listed in the INFORMATION: lines under the menu.
Inside the MakePartImage (MPI) Update pack download, you will find some additional Windows Scripts which you may find useful:
1. .\csm\e2b\RestoreE2B (run as admin).cmd - this file can be used if you have accidentally created and used a .imgPTN file on your E2B USB drive and it is 'stuck' (the CSM-Menu does not appear or it does not boot and so you cannot restore the original E2B MBR partitions). Run it from an Admin command prompt (runs a Windows 32-bit program).
This file is also copied to the image itself and should be present in the \e2b folder on the E2B drive when in CSM mode. It must be run within a full Windows environment (not miniWindows or WinPE) with admin rights.
If desired, you can run RestoreE2B (32-bit executable) once you have booted to a WinPE\Windows environment from the E2B image file. This saves you having to reboot to the CSM menu to switch back to E2B mode.
2. The file \e2b\RestoreE2B_32_64.cmd allows you to restore the original E2B partitions in both a 32-bit and 64-bit WinPE environment.
3. \e2b\SWITCH_E2B is a Windows 32-bit application that allows you to select any .imgPTN file from Windows or restore the E2B partition so it can be used instead of RestoreE2B (run as admin).cmd as long as your OS can run a 32-bit Windows .exe file.
The opposite to RestoreE2B is RestoreCSM which will restore the original .imgPTN partition that was saved when you ran RestoreE2B from your booted Windows environment. To use RestoreCSM, you will need to copy the whole e2b folder to your OS system drive first, because as soon as you run RestoreE2B, the USB partition which has the e2b folder on it will disappear! Once you run RestoreCSM you will need to unplug and re-connect the USB drive for the change to be seen by the booted Windows/WinPE environment. Only use RestoreCSM on the same drive that you ran RestoreE2B on.
4. .\Utils\Convert_all_ISOs_to_imgPTN_Files (run as Admin).cmd - This runs MakePartImage on all the ISO files in a folder (and below). To use it, make a new folder, copy all the ISOs to it that you want to convert to .imgPTN files, and then run the file as Administrator, or from the Admin command prompt in the MakePartImage folder, type:
.\Utils\Convert_all_ISOs_to_imgPTN_Files (run as Admin).cmd f:\myfolder\
If you want to skip the conversion of any ISO files, type A for Abort at the FAT32/NTFS prompt. (only valid if you typed N to the AUTO-RUN option).
Tip: type .\utils\Conand then use the TAB key for autocompletion. You can also follow it with FAT32 or NTFS and * to reduce key presses.
.\Utils\Convert_all_ISOs_to_imgPTN_Files (run as Admin).cmd folder-path FAT32 (runs with suggested filename)
.\Utils\Convert_all_ISOs_to_imgPTN_Files (run as Admin).cmd folder-path FAT32 * (runs with suggested filename and suggested size)
It is best to place the ISOs on your fastest hard disk (e.g. an SSD), then conversion will take just a few seconds for each one! Don't use a USB drive as the target drive as it will take a lot longer!
You can specify wild cards for the files you want to convert (e.g. A*.ISO) and they don't need to be .ISO files (e.g. *.zip or *.ima) (MPI v0.083+).
The target folder which stores the .imgPTN file must be an ordinary disk volume and not a Microsoft Storage Pool or virtual drive.
3. \Utilis\List_Missing_imgPTN_Files.cmd - this will list all .iso files that do not have a corresponding .imgPTN file. This is useful if the Convert_all_ISOs_to_imgPTN_Files.cmd failed on a few of the ISOs. It is automatically run at the end of Convert_all_ISOs_to_imgPTN_Files anyway.
Directly boot in UEFI Mode with Clover
If you wish to boot directly from the CSM menu to the UEFI boot files in the image (in UEFI mode) without needing to reboot, then you need to ensure Clover is present in your MakePartImage folder, before you make a partition image (.imgPTN) file. Clover is already included in the latest MPI_Tool_Pack versions.
See the ReadMe.txt file inside the MPI_Clover_Tool_Pack for details and my blog post here.
The version of Clover used in MPI is limited to FAT32 partitions that contain EFI boot files.
Tip: For MBR\CSM booting, use the file extension of .imgPTNaLBA23 for most reliable booting from a wide range of systems and ensure that you have a 2nd partition present on the E2B USB drive. Some systems try to boot a USB drive as a floppy disk unless more than one partition is present!
Clover UEFI-boot entry for direct booting in UEFI-mode.
Clover boot menu - choose the Boot UEFI Internal from LIVE/EASY2BOOT option to boot from the image's UEFI boot file (where LIVE/EASY2BOOT is the partition volume name)
For more information about Clover, use the links here.
Tip: Look in the Alternate Download Areas for translations of the CSM menu.lst file in different languages.
What does MakePartImage actually do?
The image file made by MakePartImage is an image of a whole partition starting at the Partition Boot Record.
MakePartImage can use either a folder, whole drive or ISO file (or .zip file) as the payload source.
If you have a working source USB Flash drive that contains a single partition, MakePartImage will create a new partition image from it, but the partition can be of any size.
For example, if a 32GB USB Flash drive contains only 2GB of files, you can make a 2GB .imgPTN file from it, instead of having to make a 32GB image of the whole USB partition.
This is what MakePartImage.cmd does...
Creates a virtual RAM drive with a .imgPTN 'backing file' of the size and name that you specified, using ImDisk
Formats the new virtual RAM drive (as NTFS or FAT32)
Copies the source files to the RAM drive (if a file is specified, then it extracts the files from it, e.g. .zip or .iso or .7z)
Copies over some grub4dos files that are required for the CSM Menu, from the .\csm folder (and then copies all files from the CUSTOM folder)
If isolinux or syslinux is detected in the source, then syslinux is installed to the PBR of the virtual RAM drive so that the image will boot to syslinux in BIOS mode. Also it will copy or rename the isolinux folder and rename isolinux.cfg to syslinux.cfg. Note: extra image space may be needed for this, so you may need to specify a larger size for the RAM drive. Possible syslinux versions are 4, 5 or 6. Version 4 will be used by default unless you run MakePartImage without using the MPI_FAT32 or MPI_NTFS shortcuts, in which case you will be prompted to choose a version.
Sets a Volume Label for the RAM drive. This can be specified by the user, or changed before dismounting the RAM drive.
Warns the user about UUID=, LABEL= and other strings in .cfg, .conf and .lst files and will auto-convert these for you (useful for linux ISOs - in some exceptional cases you may need to edit these files before dismounting the image). Unlike other multiboot utilities such as YUMI or XBoot, MPI does not need to recognise what distro it is, it just corrects any grub2/isolinux/syslinux parameter values into the correct values for use with a USB drive.
Dismounts the RAM drive and saves the contents to the .imgPTN file and launches an Explorer window to display the folder where the new image file resides.
The menu.lst file that is copied over is the grub4dos CSM menu that allows you to restore the original E2B MBR. Without this, the drive would always be seen as a single partition containing only the files in the .imgPTN image file. If a menu.lst file also exists in the source, it will ask you if you wish to combine them and then you can edit the \menu.lst file in the mounted RAM drive before you dismount and save the image.
Once the .imgPTN file is made, the user can mount the image .imgPTN file using ImDisk and then edit and re-save it by unmounting it.
Alternatively, you can boot to E2B and select the .imgPTN file, in order to switch the drive to the desired disk image (you can use VBox+DavidB's VMUB utility for this or a real system). Unplug and re-plug the E2B drive. The new image contents will be visible to Windows. Now you can edit the files on the USB drive. Any changes will directly affect the .imgPTN file.
If your E2B drive is 'stuck' with the single partition image installed, and you cannot boot to the CSM menu and get back to the E2B Main menu, run the 'RestoreE2B' script from a Windows system (see the 'Additional Utilities' section above) or from the RestoreE2B.cmd file in the \e2b folder on the USB drive.
You can instead run the Windows SWITCH_E2B.exe utility (E2B v1.73+ and MPI v0.055+).
A backup of the E2B MBR can be found in \e2b\MBR.BIN which can be used to restore the original E2B partitions if RestoreE2B.cmd does not work (e.g. using dd in linux or RMPrepUSB - File>Drive or BootIce). SWITCH_E2B.exe will use the MBR.BIN file if it cannot find another MBR backup sector.
N.B. Some UEFI systems will not offer the user a MBR\CSM boot option if there are UEFI boot files present on the USB drive. This means that after changing to an .imgPTN file which contains EFI boot files, you may not be able to boot to the CSM Menu and restore the drive back to the E2B menu. For these systems, you must either MBR-boot on a different system, or use a Windows system to run \e2b\SWITCH_E2B.exe to restore the E2B partitions.