I have 2 emopi. Both are Nov. 2016 builds. I had one in service for more than a year, but then I shut it down. Just 2 days ago I tried to revive the one I had in service. It boots fine, but when I connect the ethernet cable it flickers, the lcd becomes difficult to read, and my router gets hot. To me, these are indicators of a ground fault, a weak power supply, a bad ethernet cable, or a bad emonpi. I tried more than one cable with the same response. I also tried a 10W and a 12W power supply with the same response. I then tried my other emonpi and got the same response.
I have no idea how to proceed beyond reflashing the sd card, but i supect that wont solve the issue.