This article provides information regarding whether UBUNTU 16.04.7 LTS 32-BIT compatibility with the E2 series

Elo's current line of AIO's use UEFI Secure Boot. Older versions of Ubuntu such as 16.04.6, and any 32-bit version, does not support UEFI Secure Boot and therefore will not run on Elo's newer systems such as EloPOS, I-Series, or E2-Series.

1. Ubuntu-16.04.6-desktop-i386.iso doesn't support UEFI boot, and EloPOS only support UEFI boot.
2. Ubuntu-16.04.6-desktop-i386.iso kernel doesn't support 64bit CPU, and EloPOS is 64bit CPU.