Custom ROM on Jelly Pro

Got a Jelly Pro (1st gen) to use soley as an audiobook/music player. In order maximize battery, I'd like to have a custom ROM like lineage on it. But I'm not sure how/if it is even possible?

Anyone here ever run lineage (or something similar) on the Original Jelly Phone (NOT Jelly 2) and if so anyone got a guide on link on how to do it?