CREDIT GOES TO DYLAN DOXEY
I bought my 2006 in April. I for sure wanted the cassette player out from day one. In addition to that, the Navigation was belly up and I wasn't seeing anything that suggested that it could be repaired. Some updated tech was a must for me.
I was able to install an Android without sacrificing the main multi-purpose display at all.
It wasn't entirely easy. Apparently the energy monitor was designed to need the cassette player to function correctly. I don't know what the logic was there. But with some experimentation I figured out that the sole purpose of the 12 pin connector (with only two pins used) is to signal the multipurpose display that the cassette/stereo unit is installed. All the cassette/stereo unit does is apply a 70ohm resistance. I didn't happen to have a 70ohm resistor laying around, so I tried a random one from my scraps bin ...
There is also the matter of the steering wheel controls.
From left to right, that is SW2, SW1, SWG. There's no need to buy a fancy black box. You just need to connect those three lines to your new head unit as labeled. (I just happened to have a Toyota 20 pin connector that works for this in my junk bin.)
For the rest of the connections, the Metra 70-8113 adapter harness did the trick.
I'm planning to add a rear-view camera next ...