Not all of these .ISO files may boot correctly under E2B (freeBSD requires a partition type number set in the MBR and does not like overlapping partitions).
However, you can add Ventoy to the E2B USB drive. Ventoy can usually directly MBR-boot to these ISOs - see Ventoy supported ISO list here.
Use .isBSD extension
New .isoBSD file extension in E2B v1.A5 and later versions (bugfix for flashing cursor in E2B v1.B6+).
I successfully MBR-booted FreeBSD-11.1-RELEASE-amd64-bootonly.iso, TrueOS-Desktop-18.03-x64-DVD.iso, OPNsense-17.7.5-OpenSSL-dvd-amd64.iso, Nas4Free.iso and pfSense-CE-2.4.4-RELEASE-amd64.iso using the .isobsd file extension.
1. Change the file extension of your BSD-based ISO file to end in .isobsd and copy it to your \_ISO\LINUX folder (or any standard menu folder).
2. Run \MAKE_THIS_DRIVE_CONTIGUOUS (run as admin).cmd.
E2B Partition 3 must be unused\empty.
Note: When using the .isobsd file extension, E2B will switch partitions so that the E2B partition disappears. To restore the E2B partition, simply MBR-boot again or run the \RESTORE E2B PARTITION.cmd file as Administrator.
.isoBSD is for MBR-boot only, and does not work with all BSD ISOs - see bottom of page for more details.
Tip: If booting on a headless appliance (i.e. no VGA display), configure the E2B default menu option + 10 second timeout so that your ISO will automatically run from the Main Menu after a 10 second delay (e.g. using \QEMU_MENU_TEST or another system).
You can also use FreeBSD-based hybrid ISO files (e.g. FreeBSD-11.1.iso or OPNsense-17.7.5-OpenSSL-dvd-amd64.iso) by making use of a .imgPTN file (scroll down).
The 1.63 version of Easy2Boot and a new MPI Tool Pack v0.044 or later supports FreeBSD 9 and 10 'memstick' images. For GhostBSD, download the .img files and not the .iso files. For MidnightBSD, use the 'memstick' download.
If the memStick .img file contains multiple images inside it (e.g. pfSense v2.4), then this process will not work.
For OPNsense .bz2 downloads for USB drives (e.g. serial download), extract the .img file from the .bz2 file using WinRar or 7Zip and follow the instructions below.
The procedure is to use the MakePartImage process, but as the FreeBSD memstick.img files are already in the correct format for a FreeBSD partition, the .img files don't actually need converting or modifying!:
1. Create a new empty folder on the Windows Desktop (or anywhere else).
2. Drag-and-drop the empty folder onto the MPI_FAT32 MPI Desktop shortcut to make a 30MB (or as small as possible - e.g. 10MB) partition image with no payload. If prompted for a target file, use a filename with either a .imgPTN or .imgPTNA5 file extension - e.g. FreeBSD_10_1.imgPTN or FreeBSD_10_1.imgPTNA5.
Do NOT use a filename that has any dots in it because it will also appear in the E2B Menu - e.g. FreeBSD10.1.imgPTNA5 would not be a good name because the 'FreeBSD10.1' file (see below) would also be visible in the menu!
3. Copy the new .imgPTN file to a menu folder (e.g. \_ISO\LINUX, a 2nd level folder - NOT \_ISO\LINUX\MNU).
4. Copy your FreeBSD memstick .img file to the same folder that the .imgPTN file is in and rename it to match the name of the .imgPTN file but WITH NO FILE EXTENSION - e.g.
FreeBSD_10_1.imgPTN (10-30MB) FreeBSD_10_1 (NO FILE EXTENSION OR DOTS - e.g. 700MB memstick.img file renamed to match with no file extension)
Tip: Download the .xyz (compressed) non-UEFI version, e.g. FreeBSD-10.1-RELEASE-i386-memstick.img.xz and then unzip it to obtain the .img file. The .xyz files are smaller than the .img files. I also tested this with pfSense-CE-memstick-2.3.5-RELEASE-i386.img and OPNsense-18.1.6-OpenSSL-serial-amd64 (1).img.
5. Make all files contiguous on the drive.
6. Use the E2B menu to select the .imgPTN file.
Bug in MPI v0.078 and previous versions:
Do NOT use SWITCH_E2B.exe or you will not get the option to boot from the 3rd partition (was fixed in MPI Tool Pack v0.079+).
Grub4dos can access the files on a FreeBSD type A5 partition just fine as it understands the FreeBSD volume format.
To add more FreeBSD versions to the E2B USB drive, just copy and rename the .imgPTN file (or make a fresh one) and then rename the new FreeBSD memstick .img file to match it.
Note that only 'memstick' images for USB drives will work in this way. Luckily, GhostBSD .img files are in the memstick format.
5. Drag-and-Drop the FreeNAS11 folder onto the MPI_FAT32 Desktop shortcut to make a FreeNAS11.imgPTN file.
6. Copy the FreeNAS11.imgPTN file and the FreeNas11.ISO file to the \_ISO\LINUX folder on your E2B drive.
7. Rename the FreeNAS11.ISO file to FreeNAS11 (remove the .ISO file extension).
\_ISO\LINUX\FreeNAS11.imgPTN (approx 78MB)
\_ISO\LINUX\FreeNAS11 was the whole .ISO file (name must match .imgPTN file and should not contain any dots)
MBR-boot to the .imgPTN file and from the CSM menu choose the g2ldr menu option.
If the ISO is a 64-bit-only version, use a file extension of .imgPTNAUTO64 so that it is only listed on systems with 64-bit CPUs.
If the file name contains a dot, then both files will be listed in the Linux menu, so ensure there are no dots in the file name. If you really want to have dots in the menu entry, add a .txt file using \_ISO\Txt_Maker.exe.