Default Downgrade Error

I have an F320S which I want to downgrade from 20A to 11G, but when I try to install the 11G .kdz for my phone, LG Update Tool (or whatever it's called) stops at 2% when installing, and I get this message:
Quote:
21:48:33 : ********* 2Chip Model.dll input Parameter*************
21:48:33 : MODEL_EVENT : 32769
21:48:33 : PhoneBinaryPath : D:\Windows\Nedlastninger\KoreanSKT F320S F320S11G_00.kdz
21:48:33 : ModuleDir : C:\ProgramData\LGMOBILEAX\Phone\
21:48:33 : BootWaitTime : 49500
21:48:33 : UsbHighSpeed : FALSE
21:48:33 : PhoneMode : 2
21:48:33 : NewPhoneBinVersion : KoreanSKT F320S F320S11G_00
21:48:33 : ClearSI : FALSE
21:48:33 : AuthMark : 0
21:48:33 : ********* 2Chip Model.dll input Parameter End*************
21:48:36 : wParam : 20, lParam = 540
21:48:36 : MODEL DLL Event : (20, 540)
21:48:37 : Model File Count = 540
21:48:37 : wParam : 100, lParam = 51
21:48:37 : MODEL DLL Event : (100, 51)
21:48:37 : Step : TYPE_WPARAM_UPGRADE_ERROR
21:48:37 : CleanModelDll() : Free Model.dll
21:48:37 : _DetachDLL Call
21:48:42 : _DetachDLL Call End
21:48:42 : Page_Error 부분입니다
21:48:42 : 여기는 Retry 부분입니다

Is it because I'm downgrading, and it recognizes that I have a newer ROM-version and won't let me downgrade, or what? It would be very nice if someone gave me a solution, which I couldn't find by searching. Thanks in advance :P
Phone: LG G2 F320S
__________________________________
Status: Up & Running
ROM: LG KitKat 11g (Rooted)
Android Version: 4.2
Recovery: PhilZ Touch

Tablet: Google Nexus 7
______________________________________________
Status: Up &Running
ROM: CyanogenMod 11.x
Android Version: 4.4.x
Recovery: PhilZ 5.03.0


Other Devices
______________________________________________
Viewsonic Viewpad 10s (Bricked)
LG Optimus One P500 (Sold)
HTC Sensation (Up & Running)