Thanks jboxer for the credits.
I use Windows Virtual PC in XP Mode to install the .kdz file but you may be able to install it in Windows 7 by using LG_KDZ_FW-Update_OfflineFix as follows:
From the OP by adixtra at http://forum.xda-developers.com/show....php?t=1287236
1. download: LG_KDZ_FW-Update_OfflineFix (OFFLINE INSTALLER DOWNLOAD)
2. download: KDZ_FW_UPD_EN (DOWNLOAD FLASHING PROGRAMS)
3. download: ROOT USING SuperOneClick
DO NOT DOWNLOAD ANY OF THE OTHER FILES THERE!
From the OP/first page of this thread, download V21y_00.kdz
From the OP by Kairi_zeroblade at http://forum.xda-developers.com/show....php?t=1566681
download CWM-Based Recovery 188.8.131.52
Carry out the steps in adixtra's OP at http://forum.xda-developers.com/show....php?t=1287236 with the V21y_00.kdz file you downloaded by selecting it from wherever you downloaded it to.
It takes about 10 minutes to complete.
Afterwards, you will have to root it with SuperOneClick and install CWM if you want to use it for backing up, restoring, etc. (saving your butt) otherwise if you restore it will be the stock v21y installation.