The latest MSFS2020 patch breaks some liveries working but theres a fix. The problem seems to be that the livery will not load now if the livery hasnt got a model folder.

In other words the aircraft.cfg file must have a valid entry in the model=”” field. This model folder must exist and must the same name as the texture folder.

[FLTSIM.3]
title = "Airbus A320 Neo Aer Lingus Original" ; Variation name
model = "" ; model folder
panel = "" ; panel folder
sound = "" ; sound folder
texture = "EIN1" ; texture folder


The above entry in the aircraft.cfg file must be changed to;

[FLTSIM.3]
title = "Airbus A320 Neo Aer Lingus Original" ; Variation name
model = "EIN1" ; model folder
panel = "" ; panel folder
sound = "" ; sound folder
texture = "EIN1" ; texture folder


So for every livery you must create a “model.liveryname” folder with a model.cfg file inside and update layout.json file with an entry for the new model.cfg file;

{
"path": "SimObjects/Airplanes/Asobo_A320_NEO/MODEL.EIN1/model.cfg",
"size": 902,
"date": 132434199000000000
},

Maybe they will fix this, but for now it works.