I updated my 47LM4700 to 03.40.10, but I didn't notice any difference from the official 03.40.08. I can't extract the firmware file from LG's site without the AES key. There might be a chance I could figure that out from the TV itself. but the 47LM4600/4700 don't have the RS-232c service port attached and I don't feel like tearing my TV apart. The only thing I have to look at is the source, and I don't know if the source is the official or engineer source, or even past that.
When I first updated the TV from the original firmware to 3.40.08, some things changed a bit. The option for LED Dimming (when enabled in the service menu) had disappeared from the user menu. The option still exists in the service menu, and I haven't tested whether it actually works. I also can no longer find the firmware rollback option. Previously I could get to it by pressing the Settings button and pressing the '9' key 7 times. I also used to be able to force firmware upgrade by pressing the '7' key 7 times, but now I have to press the '2' key 7 times.