Currently you cannot directly boot from an ISO file via UEFI using Easy2Boot - you have to convert the ISO to a .imgPTN file first.
However, grub2 can UEFI-boot and can run linux ISOs (some of which will run even if the ISOs do not support UEFI-booting and do not contain an \EFI folder!).
The reason E2B does not use this mechanism is that some UEFI systems will only UEFI-boot from a USB disk containing both MBR and UEFI boot files - even if the system is set to boot from Legacy/BIOS devices.
This means that if you had grub2 UEFI boot files on your FAT32 E2B drive, then you can never boot to the E2B menu on these systems!
However, grub2 can UEFI-boot and can run linux ISOs (some of which will run even if the ISOs do not support UEFI-booting and do not contain an \EFI folder!).
The reason E2B does not use this mechanism is that some UEFI systems will only UEFI-boot from a USB disk containing both MBR and UEFI boot files - even if the system is set to boot from Legacy/BIOS devices.
This means that if you had grub2 UEFI boot files on your FAT32 E2B drive, then you can never boot to the E2B menu on these systems!