[LG Optimus 3D] visionastral:
Hello, I have been turning mad lately since my Optimus 3D began acting weird once I connected it to my PC to transfer large amounts of data in USB MASS STORAGE mode.

In the beginning, the transfer was ok and connection didn't show any problem. However, at a given (arbitrary) point, it just connected and disconnected by itself several times in just few seconds.

I thought it was the usb cable, so I changed it, but that didn't fixed it. Then I tried it with several other computers, and that happened randomly on all of them.

Then I thought it could be the micro-usb connector being damage, but as I closely analysed it in the computer side, I found that the phone was connecting ok, but was recognised the wrong way. (drivers were ok, as I reinstalled everything several times)

In fact, the LG update recognised the phone's model and connection. It simply didn't worked as a mass storage usb device.

I spent hours searching the web for answers about this issue, but the only thing I could found was one guy telling to remove the battery for 10 minutes in order really reset the phone's usb mode.

I did it and it worked! HOWEVER, the issue reapeared quickly once I connected the phone to the PC via USB. (it took several minutes to happen, but happened)

I finally found this forum and read a lot of complaints about LG phones.

However, it seemed to be a software error, not a hardware one. Wich was good news.

I was thinking to send the phone to LG for repair, but I had little hope they would even check such an arbitrary issue with usb connection and I thought they would simply say it's my computers fault, so I kept searching.

I finally found a similar issues with Galaxy S2 on the forums, and someone fixed it accessing the "PhoneUtil" hidden app in that phone.

This app don't exist in LG phones, but there IS a hidden menu to fix this, but you will have to install a free shortcut creator app form the market place in order to access it:

- download "ANY CUT" from the market place

- run it and create a NEW shortcut

- select ACTIVITY

- scroll down and tap on: com.lge.hiddenmenu.port_setting.PortSetting

- give the shortcut a short name like "Port Setting"

now you have created a new shortcut in your home screen (somewhere)

Once you tap on it, a menu will pop and let you choose the type of connection to be used by the USB port.

By default, "NO RETENTION" is selected.

If you want to force the phone to use the usb connection for data transfer with your PC, then select AP USB

(if you check the "retain AP USB after reboot" it will freeze your phone and you will have to long press the power button to shut it down, but it will actually work and will be set this way until you change it again)

Voila! That fixed my LG P920 Optimus 3D USB transfering issues.

If you need to make a software upgrade at some point instead of using it for USB transfer, just change the setting to "NO RETENTION" again and check the "reatin after reboot" option.

I just wanted to share this, as I found no fix for my problem in the net and I think this should be happening to someone else.

Feedback is very welcome! (even needed, just in case this is braking something)

By the way, it's a good idea to activate the "Debugging mode for USB" in settings/applications since it seems to make a more robust conection with the phone for mass storage transfer.

As why this entire issue is happening, it seems the USB conection can handle multiple transfer modes. One of those is USB Mass Storage mode (like every pendrive out there) but the other one is a LG propietary comunication mode that I suppose was done in order to have full access to the phone firmware through the computer.

The bug appears in the moment when the phone have to decide if it should engage on mode or the other.

I have noticed (since I forced the port setting to AP USB) that the phones screen will turn itself on randomly once connected and that it don't stay active even if you specifically check that option in the development menu.

I suppose the original bug is still there in someway, but at least it will not ruin the data transfers.