HP utility ISOs such as the HP ProLiant Offline Array Configuration Utility are non-standard format. HP provide a special HP format tool to convert them for use with a single-boot USB drive. The one I looked had just had a compaq, system, punchout and usb folder.
I have added a .mnu file to support these linux-based ISOs into v1.32, however, you need to extract the ISO contents and so you can only have one 'payload' at a time on your E2B USB drive, due to folder name conflict.
The basic .mnu file for hpacuoffline-8.75-12.0.iso for instance is (one line is very long!):
# Extract the ISO contents (\usb folder is not required)
# Place this .mnu file in any E2B menu folder (e.g. \_ISO\MAINMENU)
title HP ProLiant Offline ACU Image\n
kernel /system/vmlinuz rw root=/dev/ram0 media=usb ramdisk_size=353272 init=/bin/init loglevel=3 ide=nodma ide=noraid pnpbios=off usrramfs=1 vga=791 splash=silent showopts nox2apic
The important change is to use media=usb. If this does not work for your HP ISO, you will need to look at the \system\isolinux.cfg file to see what parameters are required in your .mnu file; however the basic menu format should be maintained (i.e. kernel command followed by an initrd command).
However, with v1.32 of E2B you will be able to use partition images, and so you can have any number of HP utilities on your E2B USB drive
1. Prepare a spare USB Flash drive using the HP Format utility and an HP ISO as instructed by HP
2. Make an image of the USB Flash drive using MakePartImage.cmd (you may need to pick an earlier version of syslinux when prompted)
3. Add the .imgPTN file to your E2B drive (e.g .to the \_ISO\MAINMENU folder)
4. Repeat for all other HP ISOs.