Look what came into the mail today:
I was a little concerned when I found out the serial number landed in the recall phase (supposed to be a post recall device), but the battery is of the right type (B01).
Backed up all the partitions (except userdata to MicroSD), updated the stock OS to LP5.1 (was optimizing apps in the above photo), backed up recovery a second time, and flashed TWRP. Just tested by 4.4.4 build of CarbonROM, sadly got a bootloop. No worries, my 5.1.1 version seems to be booting fine (at the setup wizard as I am writing).
Have a great 2016!