You're on the right track. But the reason OK doesn't work is because by default it's always locked to the Cable TV device on that remote. So no matter what code you choose, it still won't work. We can get around this by assigning it to the correct device like so with setup code 31295 on AUX and the appropriate EFC or Magic Code.

Press AUX, hold Setup for 2 blinks, 994, tap Setup followed quickly by 00184, OK (2 blinks)

For your LG, use setup code 10178 on TV and the steps above with 00164 instead of 00184 and TV instead of AUX.

FYI, the first digit of each setup codes specifies its device type: 1 = TV, 2 = DVD/DVR, 3 = Audio

Alternately, you could unlock channel lock like so: Hold Setup for 2 blinks, 973, CH-. But this means you'll need to be in CBL mode to operate the cable box.