[LG Optimus L90] Infinit0:
Hey, I want to say thank you to the author of this thread (and to the two people I quote), because otherwise I'd have a useless brick on my hands (and the phone wasn't even mine :P)

I have a few pointers for the people who will be trying this and don't really know **** about electricity, like me.

1. This was my setup: http://funkyimg.com/i/2vSNz.jpg (MicroUSB cable is not connected here, because this was shot after I already revived the phone. When you are doing this, the microUSB cable should also be connected.)

I got the idea from user akarb (in this post), who also posted that he had a shield on the motherboard, but he apparently was able to remove it, which I didn't know how to do, so I worked around it.

The piece of wire, that is taped to the pointy end, is a solder metal wire, so you can manouver beneath the shield. On the shield (above the test point) I taped some isolating tape, that I folded underneath the shield, so in case I touched the shield I wouldn't conduct the current to it. As I said, I know almost nothing about electricity, so I don't know if this even makes sense :)

One more thing here, if you also have a shield on and your eyes are not the best anymore; test point is "almost" right underneath where the opening of the shield starts, but not totally underneath. It is a little more withdrawn inside, so you'll have to touch it from the side.

2. User krusli had a few useful pointers here. I'll copy and paste them here and I'll add my own experience:

- The phone isn't detected on my first try - in fact, I kept poking around for an hour or so. I found that touching the test point using the wire from the top worked, but not from the side. Also, just tape the other end of the wire to the Ground (GND) point so that your other hand is free to plug in the USB cable. (-- I managed to do it form the side as I said, it took me around 3 minutes of trying to get my first recognition from the device manager)

- I plugged in the microUSB cable to the phone, and plugged in the USB end AFTER shorting the points. This is much easier compared to connecting the microUSB port after the USB port. (-- I don't really accurately remember at which point I got the recognition, but I think the USB was connected on both ends (in phone and in the computer) and I was just fiddling around, trying to hit the "test point". I plugged and unplugged the USB from the computer a few times, trying to do it as krusli described, but it's really hard to hold the wire steady while plugging the USB in the computer.)

3. The guide and the pictures were a little confusing to me at first (especially the point 1.5, where it says to short the phone resistor). For anyone as clueless as me here's the explanation; this just means connecting the GND point and the test point and keeping them connected untill you do 1.6; plugging the other usb in the computer. As you could read above, there might be some slack here and you can connect the usb to computer and then try to connect the GND and test point.

4. Use a proper USB cable and a good usb port on your computer.

This is really important. At first I used a cable which I knew was unreliable, connected to a USB port on the front of the computer case, that I also knew wasn't the best. I assume it was on of those factors that caused me to lose my connection shortly after the recogniton (the phone still showed up in the Device manager, just not under "Qualcom...", but as unrecognized USB device and it had an excalamation mark next to it). Thankfully I haven't been doing anythig with the B2b program at this point. I don't know what would happen if the phone disconnected in the middle of pushing one of the files.

On the second attempt I used an Anker cable and connected it directly to the computer motherboard, and the connection staied solid.

5. After doing everything else, I got the security error under the LG logo on boot and the phone then turned off. I solved this by putting the phone in "download mode" (hold the volume UP and plug the microUSB cable in the phone - with other end already in the computer). Then I donwloaded the LG user support tool, clicked Options -> Upgrade recovery and the program donwloaded the appropriate .kdz and flashed it on the phone.

That's what I have to contribute, in case it helps someone. I know it's scary to get to it, if you haven't done anything like it before, but it really does work, as much as I was skeptical. Thanks again for posting this guide.