I may still be wrong, but usually manufacturers try to guard against these sort of upgrades...
Originally Posted by mihai.balaci
Replacing the mainboard with one that does run webOS and selling your original one may be an option, though it will void your warranty.
And while "locked bootloader" may be an issue for flashing over USB, it may be possible to flash a chip over JTAG if you will have direct access to it, but again, opening up a TV will void its warranty
But it may be possible to try reflashing the TV over USB if someone has the correct tools, if the firmware is cryptographically signed. If all goes well, great, if not, the TV may have to be reflashed to original firmware over JTAG... and i honestly don't know if LG makes any of its firmware available in standalone packages
Another thing to think about is waiting for the newer (better?) version of webOS TV that will come out in 2015, and buying a TV that runs that