[T-Mobile LG G2x] Core Memory:
I just finished "updating". It worked but my phone was already running V21Y and rooted and with a custom ROM and Kernel. Although I had drivers which worked with previous updates/installs of V21Y, it didn't work at first, I had to install the drivers with the included driver installation utility. After it "updated" everything was still there except that it was unrooted and the ROM, Kernel were replaced with the stock ones. Now I have to root, reinstall CWM, etc.

Here's the log file content:

00:01.0 Sec :Download Start...

00:01.0 Sec :Setup communication port

00:12.1 Sec :Check Version

00:12.2 Sec :---------------------------------------------------------------------------------

00:12.2 Sec :---------------------------------------------------------------------------------

00:12.2 Sec :This Version is V21y. so Download START!!

00:12.3 Sec :We try to communicate with phone

00:12.3 Sec :---------------------------------------------------------------------------------

00:12.3 Sec :---------------------------------------------------------------------------------

00:14.3 Sec :Change DLOAD mode

00:14.3 Sec :---------------------------------------------------------------------------------

00:14.3 Sec :---------------------------------------------------------------------------------

00:20.4 Sec :We are searching new USB port...

00:20.4 Sec :Test DLOAD mode

00:21.4 Sec :---------------------------------------------------------------------------------

00:21.4 Sec :---------------------------------------------------------------------------------

00:21.4 Sec :Set NONHDLC mode

00:21.5 Sec :---------------------------------------------------------------------------------

00:21.5 Sec :---------------------------------------------------------------------------------

00:23.5 Sec :MDMWebdloadCPUSBConnected

00:23.5 Sec :Response is NAK

00:23.5 Sec :We can't notify dload status CP to AP

00:35.6 Sec :We are searching new USB port...

00:35.6 Sec :Num of partitions are 7

00:35.6 Sec :partition 3 download

00:37.2 Sec :Partition download complete.

00:37.2 Sec :partition 4 download

02:04.2 Sec :Partition download complete.

02:04.2 Sec :partition 5 download

02:06.3 Sec :Partition download complete.

02:08.3 Sec :Download complete

Because this worked without any problem with Windows 7, it is a valuable addition to update methods available. It uses a version of the SmartFlashTool for the P999. As it ran, I saw that it appears to change from CP to AP mode. The LGP999AT-00-V21y-TMO-US-MAR-11-2012_AP.bin file is an AP mode file but it appears to include the baseband update in it which is usually a CP.bin file that is flashed separately as with the P990 and Paul's hacked SmartFlashTool. I wonder if the LGP999 version of the SmartFlashTool can be hacked to work with CP.bin files like Paul's does. Also, I wonder if the full GUI can be provided like Paul's has. That would be really useful.

Addition:

I looked at the model.dll code and found:

P990Bn_dll.dll.DoDownload.DoFactoryDownload.DoFactoryDownloadMDM.ExecuteFunction.FileDLOrder.GetFileTypeStr.JudgeFile. A111

That indicates it is the same tool that Paul Hacked.

Other code indicates that it can flash CP.bin files. That may work if a P999 CP.bin file is in the same folder as the Ap.bin file.

I am not willing to experiment that far with my phone as it is a PITA to resurrect it when it gets bricked. Braver souls will have to try that.