E2B Payload File Extensions

To change the way a payload file will be executed by E2B, you can change its file extension. 
A whole range of 'Special' (non-standard) E2B file extensions are recognised by Easy2Boot (see below). 
If you are not sure what file extension will work best and it is an ISO file, use .isoask so that you can test all of them until you find one that works! Read more here. File extensions are not case-sensitive.
If you wish to see exactly what grub4dos code is run for each file extension - please look at the code in the file \_ISO\e2b\grub\QRUN.g4b. For example:  the lines under the label :.isoDOS01 in QRUN.g4b will contain the grub4dos commands that will be run for any xxxxx.isoDOS01 file.
When selected from the E2B menu and if the extension is recognised by QRUN.g4b, the file will be executed. The file extension determines how it is executed by E2B and grub4dos.
Note: All files, except those files with file extensions of .bat, .xml, .cmd, .txt, .bat, .exe and . (no extension), are added as menu entries, but only files with the files extensions listed below will be valid.

Tip: Always try a filename with no spaces or special characters first. If it works, then you can try renaming it - e.g. first try Windows_10_x64.iso - if it works then try 'Windows 10 64-bit.iso' so that the menu entry is more readable.


File extension suffixes ('pwd', '32' or '64', '4GB', '3GB' or 'AUTO')

If you add pwd  (e.g. fred.isopwd) to almost any file extension (with a few exceptions such as .WIM and .VHD files), E2B will prompt you for the password which is defined by the variables 'pwd' or 'menupwd' in your MyE2B.cfg file. The default password is easy2boot. See here for more details.

File extensions suffixes only work for standard E2B menus (but you can use .iso32 or .iso64 in Windows Install menus - E2B v1.94+).

  • If you add AUTO to the end of a .imgPTN family file extension, the user will not be prompted before switching the image and loading the CSM menu (.imgPTNxxxx files only).
  • If you add 32      to the end of the file extension, the payload will only be listed in menus on 32-bit systems (v1.62+).
  • If you add 64      to the end of the file extension, the payload will only be listed in menus on 64-bit systems.
  • If you add pwd   to the end of the file extension, the user will be prompted for a password before it is run.
  • If you add 4GB   to the file extension, the payload will only be listed in the menu if the system contains more than 4GB RAM (v1.A4+).
  • If you add 3GB   to the file extension, the payload will only be listed in the menu if the system contains  less than 4GB RAM (v1.A4+).


Ubuntu.iso64                     will only appear in the E2B menu if a 64-bit CPU is in the system. 
Clonezilla.imgPTN32           will only appear in the menu if run on a 32-bit CPU.
Hirens_15.2.isowinvhpwd    will ask the user for a password (set by pwd or menupwd) before it will boot to the file
Dium.imgPTNlbaa23auto     will not prompt before switching the image
Ubuntu_64-bit.iso4GB         will only appear in the menu if system has more than 4GB of system memory
Ubuntu_32-bit.iso3GB         will only appear in the menu if system has less than 4GB of system memory
You can combine suffixes as long as they are in the order .xxxx[AUTO][32|64][pwd]  where xxxx is a valid E2B file extension (v1.78+),  e.g.
If you use a matching .txt file for a payload file, then the menu will always be listed, unless the .txt file also tests for 32-bit or 64-bitness. e.g. If using files fred.iso64 and fred.txt, a menu entry will be displayed on both 64-bit and 32-bit systems, unless you add extra code to the .txt file to check which CPU is present - see here for details.
You can also 'hide' payloads, so that they are not listed in the menu system - see here.


.ISO filenames ending in the letter Q.iso or q.iso (Q\q for 'quiet') and with a .ISO file extension (e.g. thisismyisoQ.iso) will suppress the 'autosuggest' text usually displayed by E2B. Useful for WinBuilder-based WinPE ISOs which must use the file extension .ISO. Not case sensitive.


No 'not-contiguous' warning messages are shown if the file is not contiguous (NCQ = not contiguous and quiet). Useful for WinBuilder-based WinPE  (use *NCQ.ISO) and other WinPE ISOs which are not contiguous but still boot OK (v1.98+). Not case sensitive.


If a payload file also has a matching .txt file of the same file name (e.g. Ubuntu.iso and Ubuntu.txt) this will also automatically suppress the 'autosuggest' text usually displayed by E2B.

List of all file extensions recognised by E2B

Recognised file extensions and their run actions are listed below...
.iso - maps the ISO file (if contiguous) and also creates a new partition containing the ISO contents - use for linux and WinBuilder WinPE ISOs and others.

Tip: Some payloads require a .iso extension (e.g. WinBuilder ISO files). For 'quiet' booting with no auto-suggest prompt, ensure the last letter of the file name ends in q or Q - e.g. WinPESE10_2016_x86q.iso. Create a matching .txt file if you want to change the menu entry text.

.isodef, .isodefault - same as .iso but the QRUN auto-suggest feature is disabled so the user doesn't get prompted with an alternative suggestion.
    Tip: use
.isodef64 for 64-bit ISOs so that they are not listed in the menu on 32-bit systems. WinBuilder ISOs must have a .ISO file extension.
.isoask - asks the user each time which of the special options should be used - useful to determine which extension works best.
.isodd - same as .iso but never shows any auto-suggest prompt (even if ISOASK variable is set then E2B will not ask how you want to run it and it will boot in the same way as a .iso file).
.isomem - loads the whole ISO file into memory and also creates a new partition containing the ISO contents (if contiguous) - use for non-contiguous linux ISOs and XP-based ISOs and Hirens ISOs (may not always work depending on payload type!).
.isowin - as .isomem but does not load ISO into memory unless it is non-contiguous, and then boots from setupldr.bin or \ntldr or \bootmgr if possible - use for WinPE ISOs - e.g. Symantec Recovery ISOs
.isolinux - tries to boot from ISO using isolinux.bin or \boot.isolinux.bin or \boot\syslinux.bin if possible
.isogrub - tries to boot from grldr within the ISO
.isoforce - loads firadisk floppy disk image and forces grub4dos to boot from the ISO even if it doesn't think it is bootable - use for CentOS ISOs
.isofira - maps the whole ISO file (if contiguous) or loads it into memory (if not contiguous) and also loads the firadisk floppy image as fd0 also if Windows ISO, will load ISO as virtual cd - use for BartPE\Strelec PE based ISOs
.isofira01 - maps the whole ISO file (if contiguous) or loads it into memory (if not contiguous) and also loads the firadisk floppy image as fd0, swaps hd0&1, also if Windows ISO, will load ISO as virtual cd  - use for BartPE\Strelec PE based ISOs
.isomemfira - loads the whole ISO file into memory and also loads the firadisk floppy image as fd0 - use for BartPE\Hirens XP PE based ISOs
.isomemF01 - loads the whole ISO file into memory and also loads the firadisk floppy image as fd0, swaps hd0&1 - use for ERD/MSDaRT 5 XP ISOs
.isowinvH - loads the ISO and also WinVBlock as a floppy image - does not swap hdo/hd1 - useful for booting Hirens CD and DLC multiboot ISOs
.isoHW - combines .isoPE with .isowinVH - use for Hirens\DLC ISOs which boot to WinXP and Win7/8/10. For correct Win7/8/10, a Removable E2B USB drive or Helper Flash drive is required - otherwise manually run \_ISO\e2b\firadisk\LOADISOPE.cmd after booting to Desktop. v1.78+.
.isomemwinv - loads the ISO into memory and also WinVBlock as a floppy image - useful for booting ERDCommander, BartPE and other XP PE based ISOs if they are not contiguous
.isogz - loads the ISO into memory - use for a gzip compressed ISO.
.isoBSD - loads a .imgptn partition image file as ptn 1 and the BSD ISO as ptn3 and then boots to BSD (E2B v1.A5+). Note: This swaps out the E2B partition with a small FAT partition but on the next MBR-boot, the E2B partition will be restored.

.isoe0 - used to boot Windows PE ISOs which give a blank screen after booting on some systems that have a buggy BIOS. - e.g. some Dell PCs - see here for details.
.isomemE0 - as .isoe0 but loads ISO into memory. - e.g. some Dell PCs - see here for details.
.isowinvE0 - as isowinv but with a special e820cyles=0 patch to boot WinPE-based ISOs that give a blank screen after loading - e.g. some Dell PCs - see here for details.
.isowinvHE0 - as isowinvH + e8020cycles=0 patch (see above)
.isoPE - use for WinPE v2/3/4 (Vista and later) WinPE ISOs. If the extension is .isoPE then when wpeinit is run by WinPE, it will mount the .isoPE file as a virtual CD/DVD drive letter. Note: This requires a USB Flash drive (or 'Helper' flash drive) - E2B v 1.07Beta and later versions only. The drive letter can be changed too. Boots to /bootmgr.
.isoPE01 - as .isoPE but swaps hd0 and hd1 over so that the internal hard disk is hd0 - useful for diagnostic WinPE's that expect to be booted from a CD and Vista/7/8 ERD/MSDart. Boots to /bootmgr.
.isoPECD - as .isoPE, but boots from the ISO boot code instead of bootmgr - use for 'compound' ISOs which have their own boot menu and can boot to PE and other payloads. E2B v1.81+
.isoPE01CD - as .isoPECD but swaps the USB drive with the first internal HDD - use if the ISO gets 'confused' by the USB drive being disk 0 during booting. E2B v1.81+
.iso01 - same as .iso but swaps over hd0 and hd1 so hd0 will be the internal HDD. (v 1.11 and later)
.isoDOS - use for DOS-emulation bootable ISOs which normally load CD drivers to access the CD, all CD contents will be found on the B: FAT32 volume once booted to DOS. Note: DOS 6 cannot access the FAT32 B: volume - use DOS 7 or later.
.isoDOS01 - as .isoDOS but swaps over the USB boot drive with the internal hard disk so that the internal HDD is drive 0 - use for Win98 Install ISOs, etc.
.isoPUP - use for Puppy linux and other similar linux ISOs
.isomacpup - use for Macpup ISOs (modifies the ISO to remove (cd) in menu.lst)
.isopersist - use for ubuntu (casper) isos + persistence files. E2B v1.98+
.isoWB - use for WinBuilder PE ISOs based on Vista or later versions of Windows (deprecated - use .iso now) - see here for details.
.isonousb - loads ISO as CD (0xff), maps USB drive as fd0, removes USB drive from BIOS hard disk list.  Useful for DOS if you don't want your USB drive to appear as a hard disk. v1.61+ more details here
.isoBF - permanently patches the ISO file to remove bootfix.bin. This patches the ISO file so that it will not ask the user 'Press any key to boot from CD/DVD...' on booting. Once patched, you can rename the file to a different extension if you wish (v1.76+).
.isoDPMS - loads XP 32-bit SATA\SCSI\RAID driver - used for DaRT5\ERD5 XP 32-bit based ISOs (only works with DPMS version of E2B). E2B v1.A7+).
.gzmd - for compressed .gz format file, loads memdisk and then the .gzmd file using initrd
.krn, .lkrn - kernel files (such as used by iPXE and netboot.xyz) (v1.78+).
Note: Do not use spaces in filenames for .wim, .VHD and .VHDX files (or you will get Error 0xc000000f).
.vhdboot - a bootable .VHD virtual hard disk image (must not be a dynamic vhd) - boots vhd as hd0. All boot files must be inside the VHD file. Typically used for XP VHDs. (Note: equivalent to .vhd in earlier E2B versions - now changed to .vhdboot in E2B v1.69+). v1.74+ also adds in a firadisk 'load vhd' command for vhd's that contain the firadisk driver.
.vhdmem - same as .vhdboot but the whole vhd file is loaded into memory (use if .vhd crashes and for faster operation once booted - obviously needs loads of memory!). Uses WinVBlock for XP-based PE ISOs.
.vhd, .vhdx - NT6-based (bootmgr) .VHD and .VHDX file for directly booting Windows 7/8/10 .VHD virtual hard disk files. e.g. a 25GB WindowsToGo VHD can be directly booted to. Note that you may need to add a copy of bootmgr to the \_ISO\e2b\grub\DPMS\NTBOOT.MOD folder as bootmgr is not included in the E2B download for copyright reasons. The vhd file does not need to contain bootmgr or a valid BCD. The vhd file does not need to be contiguous. v1.69+. Note: suffixes 64 and 32 (e.g. .vhd64) are not supported.
.firavhd, .vhdfira - loads a .img image file as a hard disk image (hd0) and adds a firadisk virtual floppy to force the firadisk driver to load the image on boot (v1.74+).
.vhdgrldr - Load a vhd as hd0 and boot to (hd0,0)\grldr (grub4dos inside the VHD) or if not exist (hd0,0) PBR or if not exist (hd0) MBR (v1.75+). Try it for non-Windows VHD files.
.wim - NT6-based (bootmgr) .WIM file for directly booting Windows 7/8/10 .wim files containing a RAMDisk PE3 image. Only WIM files containing a single image are supported (first image is booted). Note that you may need to add a copy of bootmgr to the \_ISO\e2b\grub\DPMS\NTBOOT.MOD folder as bootmgr is not included in the E2B download for copyright reasons. The wim file does not need to contain bootmgr or a valid BCD. The wim file does not need to be contiguous. v1.69+. Note: suffixes (e.g. .vhd64) are not supported.
.zip - uses memdisk to load a zip file into memory as a floppy disk (e.g. use for dos622.zip which contains dos622.ima)
.bin - use for binary executables such as memtest86.bin
.imghd Swaps over hd0 with hd1, the image is directly mapped if contiguous or loaded into memory if not - image is mapped as hd0
.imgmemhd, .imgmem - Swaps over hd0 with hd1 and maps the file as hd0 in memory using --mem
.img, .imgfd, .ima, .imafd, .imgmem, .img.gz, .ima.gz, .imagzmem, .gzfd, .imamem, .imgmemfd, .imgfd - These will all cause the file to be loaded into memory and be mapped as a floppy disk image.
.imarw - loads file as fd0 but not into memory - this means you can change the contents of the 'floppy' when you boot to it and the changes will be persistent (v1.54+) - i.e. the file contents may be changed the next time you boot from it! You can thus add or delete files once you have booted from the image. Must be contiguous.
.imgfdhd01 - loads floppy disk img file as fd0 into memory and swaps hd0 with hd1 - use for KonBoot fdd image where hd0 needs to be the internal hard disk and not the USB boot drive (E2B v1.08 and later).
.imgnousb, .imanousb - loads a floppy image into memory as fd0, maps USB drive as fd1, removes USB drive from BIOS hard disk list. Useful for DOS if you don't want your USB drive to appear as a hard disk. v1.61+  more details here
.imafdhdd0 - loads file as a large floppy (not loaded into memory if contiguous) as fd0, maps internal HDD as hd0, no other drives visible, then boots to IO.SYS (DOS) or KERNEL.SYS (FreeDOS) or boot sector. For instance, convert DOS-based ISO to .imgPTN file, add DOS boot files and rename to .imafdhdd0 (E2B v1.77+).
.imghdlinux - finds a type 0x83 partition in the disk image file and attempts to boot from it. Must be contiguous. (v1.76+)
.imghdPT - as .imghdlinux, but the partition type should be set first using 'set PT=0xhh' where hh is the hex partition type - e.g. 0x83 or 0xAF. You can use this in a .mnu file by setting PT (e.g. set PT=0x83) and then calling /_ISO/e2b/grub/qrun.g4b force.imghdPT $HOME$/xxx.img. (v1.76+)
.dmg and .dmgHFS - Single-partition HFS+ bootable partition type AF .dmg files (usually Hackintosh Installer files) - e.g. Yosemite-Zone.dmg. see here.
.HFSptn, .HFS - for bootable partition images of an HFS+ (partition type AF) - e.g. as made by UniBeast. see here.
.haiku, .imgBeOS - for Haiku 'anyboot' images - makes a ptn #4 entry for type EB on the USB drive. see blog here.
.cfg - These files are E2B configuration 'theme' files and should contain the contents of a valid MyE2B.cfg file beginning with !BAT. When selected it will overwrite a dummy \_ISO\MyE2B.cfg file (which should be blank and at least as big as the .cfg file selected) and relaunch E2B so that the new Menu settings in the \_ISO\MyE2B.cfg file take effect. (v1.55+). The \_ISO\MyE2B.cfg file must be at least as big as the selected .cfg file. The \_ISO\MyE2B.cfg file should be contiguous. A large blank file, suitable for use as the \_ISO\MyE2B.cfg file can be found at \_ISO\docs\mythemes\$Default E2B Menu.cfg. See the ReadMe.txt file for more details. Useful for switching to different 'skins'.
.txt - used for 'title' or 'iftitle' menu entries. .txt files are ignored unless there is a payload file of the same name in the same folder - see here.
.bmp, .jpg - load file as background wallpaper (E2B v1.A1+). Any animation should be stopped first using F2, if wallpaper will not change.
.uni.gz, .f24 - load font file (.uni.gz is assumed to be 16 pixel high font, .f24 is assumed to be 24 pixel high font) (E2B v1.A1+).
The following extensions are no longer supported in E2B v1.78+, just add '64' to the end of the normal extension - e.g. .iso6401 doesn't work but is the same as  .iso0164
.iso64PE, .iso64PE01, .iso64mem, .iso64win, .iso64linux, .iso64grub, .iso64force, .iso6401, .iso64dd, .iso64gz, .iso64e0, .iso64meme0,  .iso64pup and .iso64WB - 64-bit file extensions - these will only be listed in the menu if the boot system has a 64-bit CPU. Instead, you can just add 64 to the end of any payload file extension (e.g. .imgPTN64). They have the same actions as their equivalent, non-xxx64 extensions (e.g. .iso64PE01 will run exactly the same code as .isoPE01).  

.imgPTN Partition image file extensions (v1.51+)

All .imgPTNxxx files MUST be contiguous.
Suffixes that can be added for .imgPTN files (not case sensitive):
  • a=active - marks the first partition as active (bootable). An active partition may be required for some WindowsToGo first boot-time images to avoid a 'Windows could not complete' error on first boot.
  • LBA=forces BIOS to use LBA addresses
  • 23=Partition entries 2 and 3 will be kept so they are accessible in CSM mode (add '23' to the end of a valid .imgPTN file extension)
  • na=not active - does not mark any partition as Active (bootable)
Note: The partition image extensions .imgPTN, .imgPTN23 or . are the most often used.
.imgPTN, .imgPTNLBAa, .imgPTNaLBA - (a=active) Makes the first partition Active. removes all E2B drive partitions and replaces them with one partition pointing to this partition image. The E2B files must be installed on the first partition and grub4dos must be installed to the MBR. The .imgPTN file must contain grldr and a special version of menu.lst. Usually, an .imgPTN file is made using MakePartImage.cmd.
Note: if the file extension is just ".imgPTN" and there is a hidden Type 21 partition present (as created by RMPrepUSB or the MAKE_E2B_USB_DRIVE.cmd batch file by default) then the hidden partition will not be removed when you switch parititions. If you think this may be preventing the firmware from 'seeing' the UEFI boot file, try a file extension of .imgPTNLBAa instead.
.imgPTNLBA - Modifies the partition table to force the BIOS to use LBA addressing but does not make the first partition Active. 
.imgPTNAUTO - same as .imgPTN but no user prompt to switch partitions - the CSM menu is immediately displayed with no user warning messages. See Sample_MyE2B.cfg file for a setting that will auto-run all .imgPTN files.
.imgPTNna, .imgEFIna - (na=not active) - same as .imgPTN but the partition is not marked as active.
.imgPTNa - same as .imgPTN but the partition entry uses CHS not LBA.
.imgPTN23 - same as .imgPTNLBAa23, partition entries 2 and 3 are not removed (E2B v1.99+)
.imgPTNLBA23 - same as .imgPTNLBA but partition entries 2 and 3 are not removed.
.imgPTNaLBA23, .imgPTNLBAa23 - same as .imgPTNlba but partition entries 2 and 3 are not removed and partition 1 is made Active. This allows you to boot from a Windows image file but still be able to access the 2nd and 3rd partition on the E2B USB Hard disk. v1.37+
.imgPTNa23, .imgPTN23a - same as .imgPTNa but does leaves partition entries 2 and 3 in the partition table - use for WinPE/WinToGo images on E2B USB hard disks where you want access to the 2nd and 3rd partitions when you boot from the image.  v1.37+
.imgPTNA5 - For use with a 2nd FreeBSD image file. Usually the .imgPTNA5 file is made from an empty folder and so just contains the CSM menu files. It is used in conjunction with a larger disk-image file of the same name but with no extension. This 2nd file is a FreeBSD 'memstick' image file which is a disk image containing a bootable FreeBSD A5 partition. An extension of .imgPTN can also be used with the same behaviour.
(no file extension) - If a *.imgPTN* file of the same name also exists (e.g. fred.imgPTNLBAa and fred), then when switching to fred.imgPTNLBAa, the file fred will be used as partion #3.
If a 2nd image file exists with the same file name but with no file extension (e.g. Win8_1.imgPTN and Win8_1) then the 2nd image will be mapped to Partition 3 (even if .imgPTNxxx23 is used for the first partition image). Both files MUST be contiguous.

Using File Extensions with E2B

For instance, if you have fred.iso and it is a BartPE XP ISO, rename the extension to fred.isomemfira and it will be loaded into memory and a firadisk floppy image will also be loaded. If you just leave it as .iso, and it is contiguous, it will be directly mapped and no firadisk floppy image will be loaded and it may BSOD!
.xxxxxxpwd - add pwd to the end of any file extension in a normal Menu Folder and E2B will prompt for a password before booting from it. See Sample_MyE2B.cfg for more details.
If you want a different menu title to be used (rather than just the name of the file used in the menu), then  mak e a ne w .t xt file  using Notepad. For example, if you have DOS622.imagzmem and you want a different title, add a new file called DOS622.txt to the same folder and add your replacement title line in the file (must start with the lower-case word 'title') - e.g.
title MS-DOS 6.22 Floppy Disk\n This boots the file DOS622.imagzmem

More extensions can be supported by editing the \_ISO\E2B\grub\QRUN.g4b grub4dos batch file and adding a new extension section of code to the batch file. Let me know if you want me to support a new extension in the QRUN.g4b file for the next version. 

Tip: If you have an ISO file which does not boot correctly, rename it to .isoask - then you can try all of these options to see if any of them will work correctly.
Note: By using a \_ISO\MyE2B.cfg file, you can configure E2B so that only the filenames are listed in the menus, i.e. the files can be listed in the menu with or without their file extensions (EXTOFF).

Suggested File Extensions to use for different ISOs/payloads

  • Linux ISOs - just keep as .iso (see here if any problems)
  • Puppy Linux - try .isopup
  • BartPE/XP/XP Rescue ISOs - rename to .isowinv or .isomemwinv (if blank screen after boot, try .isowinve0 or .isowinvHe0)
  • Hirens ISOs - rename to .isowinvH or .isoHW (or .isomem for slow loading but faster operation) - or else try extracting the \HBCD or \DLC or \DLC1 folder to the root of the Easy2Boot USB boot drive. See here for more details. For multiple Hirens with full functionality, make a .imgPTN file from each one using MakePartImage.
  • Windows Install ISOs - these must be placed in the correct \_ISO\Windows\xxx folder (can also convert to .imgPTN for UEFI-booting)
  • HDDR2011 ISO - compress it to .gz file and use .isogz
  • Windows based ISOs that give a blank screen when Windows loads - use .isoe0,.isowinve0 or .isowinvHe0 - due to buggy BIOS!
  • WinBuilder WinPE (v2/3/4) ISO files - use .ISO for WinBuilder ISOs - do NOT change extension. Else try .isomemF01 or .isoPE01 - see here for more info.
  • UEFI ISOs or MSDaRT ISOs - Create a FAT32 .imgPTN file using MakePartImage.cmd
  • Windows To Go - create an NTFS .imgPTNA file using MakePartImage - see blog
If you are still having problems, check the \_ISO\docs\Sample mnu files folder to see if there is a .mnu file you can use (or modify slightly). 
You can also ask for help on the reboot.pro forum.
There are also useful blog posts about E2B payloads and methods listed here.
Finally, if all else fails, contact me and I will try to help.

Compressed payload files

You can compress some types payload files (e.g. .ima) to a gzip format (e.g. using 7Zip) or for better compression, use a special LZMA format (using the LZMA tool in the \_ISO\docs\E2B Utilities folder). 
In general however, I suggest you do not compress your payload files, perhaps except for some DOS-based images.
Compressed files must be decompressed and the entire file loaded into memory first before they are booted to. E2B\grub4dos automatically detects if a file has been compressed to gzip or LZMA format. The file extension is not used by E2B to determine if a file is compressed or not. For instance, a LZMA-compressed DOS floppy image can be named .ima or .imagz. However, we need to ensure the E2B loads the whole payload file into memory and does not attempt to boot directly from the compressed payload file. E2B can recognise a variety of file extensions that contain the characters 'mem' (e.g. .isomem, .vhdmem) and these file extensions can be tried if you want to try booting from a compressed file, because it will force the source file to be loaded into memory and decompressed before booting from it.
Some payload files will boot successfully when compressed to gzip or lzma format using 7Zip (.gz) or LZMA (see \_ISO\docs\E2B Utilities\LZMA folder). For instance DOS floppy disk images will still work if compressed. E2B\grub4dos must decompress these files by loading them into memory first, this may take a while for large files. Also, any boot code which is loaded from the compressed file will not be able to access the compressed source file (e.g. ISO file) once it starts to boot, because the source file is in a compressed state which will not be understood by the boot code. Further, E2B\grub4dos cannot use the partnew command to map an ISO or .imgPTN file to a partition table, if the file is compressed and so many payloads will be unable to fully boot if they are in a compressed format. For these reasons, only payload files that can be loaded and executed from memory, such as DOS floppy images and simple, single-stage linux ISOs (.isomem), should be compressed.
The file extension .zip can be used to boot from DOS floppy images that have been compressed using the ZIP format because E2B will use the memdisk utility to decompress the zip file and map it as a floppy image.