I have resolved this vesa mounting issue with retro fit to my vesa TV mount. Like many of you, I had an existing television mounted to my wall with a standard vesa mount, and when I purchased the 55" OLED, I was a little put off by LG's proprietary mounting system. I wasn't about to rip my mount out of the wall to re-install their mount, so I created my own solution. I will start by saying that this is in no way supported or probably approved by any manufacturer but it works. So, at your own risk boys and girls
. I have attached some pics as well so you can get a visual understanding of the solution. You will need to purchase about 20-25 dollars worth of supplies from your hardware store as well.
(2) 10" flat steel bars rigid enough to not bend in your hand very easily or at all.
(2) 4-6" pieces of metal strip bracing with holes.
(2) screws for the metal strip bracing
(2) wing nuts for the screws
Take one of the 10" flat steel bars and have the hardware store drill two holes in the center which are 4 3/4" apart. (120mm). These need to be in a straight line, and the holes need to be big enough to fit the screws for your vesa mounting bracket.
Take the 10" flat steel bar with the holes drilled into and screw it into the back of the OLED in the bottom two mounting holes. Use the existing bracket's mounting screws if you can. The LG ones are are too short. Do not fasten all the way at this time, as you will need some wiggle room to slide the metal strip bracing under it.
Take out the LG white screws from the back of the set. Remove the vesa mounting bracket from your old tv and set it on the back of the new tv on top of the steel bar. Line up the top holes of the vesa bracket with the top two 200mm holes in the LG and tighten with the screws from the existing vesa bracket.
Slide the two metal strip bracing pieces underneath the steel bar with the holes on the bottom of the tv, out side the mounting screws. Use a level and make sure your mount is even, then tighten the two bottom mounting screws.
Place the second flat steel bar on top of the first one and on top of the vesa bracket. Slide the screws through the metal strip bracing and secure with the wing nuts to firmly tighten the whole apparatus together. This must not have any movement at all.
Do another level check and make sure everything is without any movement. Then hang the whole thing on your wall mount or arm.
In the picture with the retro fitted bracing, I moved to top metal bar over so you could see the bar underneath, so it's not all tied down yet, but you should get the general idea.
Hope this helps!