LG seems to be very quick rolling out new updates for its Flagship devices. Recently they rolled out the latest Android 6.0 Marshmallow update for its 2014 flagship phone, LG G3. The update has started rolling out via OTA. But it is gradual roll out, since it may take couple of days or weeks to reach your region, and depending on your carrier.
But if you dont want to wait for so long to taste the new Android taste, here is an alternate way. Dont worry, this is official process using official LG tools. It will not harm your phone at all, unless you do the process properly as mentioned in this LG G3 Marshmallow Installation Guide. The update not only brings lot of new features but also so many new security features for your phone as well as data stored on it.
So, if you want to Manually update your LG G3 to Android 6.0 Marshmallow, download the LG Flashtool and the Marshmallow Update package from below and follow the steps provided in the above mentioned guide. If you need any further help, feel free to use the comments box below.