Some linux install ISOs, such as debian-based ISOs, will boot to a Live OS fine using Easy2Boot straight from the .ISO file.
However, if you want to install linux from the ISO, some linux installers specifically look for a CD-ROM drive rather than looking for the installation source files, or they do not automatically mount the 4th partition, which E2B has mapped to the ISO file by grub4dos, and so the installer cannot find the source files.
Often, however, there is a simple solution. When installing linux onto another device, you just need to specify the source device. E2B changes partition #4 so that it points to the ISO file that we are booting from. So we just need to specify that partition as the 'cdrom'!
Here is an example using debian-8.1.0-i386-CD-1.ISO.