Hey guys I want to comment that I succed flashing KDZ bigger tan 1GB with this methot. Previously I was using CM11.
It was ver hard, first time i tried on my 32 bits Windows seven laptop and nothing, then I moved to my 64bits one and no problems.
Recommendatios:
Delete every LG driver/program, restar and begin from zero.
Follow steps carefuly one by one (dont forget to kill LG MOBILE SUPPORT TOOL after its installation)
I can see that problems begin when using In R&D Test Tool window,
What I did:
7) In R&D Test Tool window,
Select Type = 3GQCT (top left hand side)
PhoneMode = DIAG (top right hand side)
Select kdz file = click to select your LG stock rom *.kdz
Click "Normal web upgrade test" (bottom right hand side)
Then another window will pop up, click "Upgrade Start" button U MUST WAIT AND WAIT A LITTLE BIT MORE HERE
Choose as stated and if new firmware download refuse to start, then restart program again and from options, choose UPGRADE RECOVERY and wait. IT WILL WORK
If after instalation you cant pass LG logo, just hard reset (from vol down and power buttons)
Hope to be able to help someone