Looking for baseband upgrade or downgrade for your LG optimus one? You came to the right place!

I assume you are looking for upgrading and downgrading basebands because you recently installed a custom ROM and unfortunately you got no network signal. This is because your installed ROM is no longer applicable for your baseband.

Old baseband is for froyo and new baseband is introduced on gingerbread. If you have updated your Optimus One to official gingerbread firmware then you have the new baseband already and you can use custom roms that are based on the new baseband but you can no longer use ROMs that require old baseband like mik_os, megatron, void etc unless you flash the old baseband again.

You can check your baseband version under Settings > About Phone > Baseband Version

If you see V20x it means you are using new baseband on the other hand V10x means old baseband.

We have two options to flash basebands, one is by KDZ and the other one is LGMDP. We will be using the latter as I personally think it is safer because KDZ wipes everything.

Before we start please note that I am not responsible if you brick phone while flashing, if you follow my steps correctly then it is most likely that you won’t brick your phone.

First download files that you need:

P500-v20G-baseband.7z, P500-v10E-baseband.7z

Updating to new baseband

  1. Unzip P500-v20G-baseband.7z
  2. Open LGMDP-1.5.exe
  3. Click Select Port
  4. Tick the correct port and click Connect.
  5. Browse Image Folder (Open P500-v20G-baseband unzipped folder)
  6. You will encounter warning messages, just click OK. Don’t change anything from this window
  7. Close LGE Mobile Security window
  8. From the following window click download
  9. The application will backup your IMEI and MACs to NV2 file
  10. Wait until flashing is complete. Don’t do anything unless it says it’s completed. It will boot to emergency mode, reboot, restore NV2 backup and reboot again. If you are still unsure I have created a video to demonstrate the steps above.

Same process if you are downgrading, you just need to use P500-v10E-baseband.7z instead.

Thanks to doktornotor for making the original tutorial in xda forum.