Guys, I created a tutorial instructing on how to use LG Flash Tool. I explain with much more details the difference between Normal Flash and CSE Flash, and which one you should use depending on what issue you're facing or whether you have stock or custom ROM installed etc.
This tutorial was targeted specifically to flashing stock firmwares for LG Optimus G (E975/E977), but it most likely applies to other LG phones as well, as LG Flash Tool works will pretty much all current LG smartphones. Although the document was written in Brazilian Portuguese, you can easily translate it to English, or just ask me so translate the most useful sections. Here's the link:
Again, I can't thank this tool developer(s) enough for his effort, this tool saved my as* several times, and works much better than KDZ Flasher. Thanks mate