Happy to report to anyone with a 2012 Honda Civic or the other 2012 Hondas with the built in USB/AUX ports and a Mytouch4g (Android 2.2) - the built in USB port reads the sdcard and enables folder browsing and music to play. I had to plug it in a few times over a few days before it finally started working.

I was listening to my XM radio via the AUX input and I noticed all of a sudden the USB logo appeared on my i-MID so I hit the AUX button again and it switched to USB mode and my music started coming from the phone instead of the XM tuner.

Unfortunately you can not access Google Music online songs through the USB (you can play any "offline" Google Music song because those are saved on your hard drive and not streamed), however you can use the cars AUX connection to play Google Music songs through the cars radio via your headphone jack.

Of course you need to make sure your phone uses USB mode to turn it self into a hard drive instead of "charge only"

Android 2.3.5 no good either
 

I've got a Motorola Cliq running Android 2.3.5 (CyanogenMod) and I, too, can't get USB Mass Storage mode to be recognized by my 2012 EX's iMID; yet a USB flash drive works fine.

So USB Mass Storage and USB Flash Drive aren't as identical as we thought?

CDFS Partition?
 

I found this thread that gives some legitimate sounding explanation for what may the problem. Does this make sense to anyone?

Somehow got it to work
 

FWIW, I somehow managed to get it to work. I'm not sure if it's because I turned off USB Debugging (something I've had on for months), or some weird sequence of events when I turned on/off mass storage in quick succession while re-plugging my cable. This at least confirms that it's not an absolute hardware limitation.

Yes, turn USB debugging off as it will not allow your car to use your phone as a mass storage device if debugging is enabled.

Even after turning it off, it's flaky. If I plug it in, turn on mass storage, and then rip out the cable, and then do it again within a few seconds, it works every time!

Sadly, when I turned off my car at the gas station and then later re-started the car, I had to do it all again.

I just got the 2012 civic lx. I have a Samsung Charge. Still not supported. Anybody have anymore info on this? Debating if it's worth getting an iphone. Never really been a huge apple fan but... Thoughts?

I have a samsung charge that does the same thing. Says it's not supported. (2012 civic lx) How my buddy told me to get around it, you have to have an adapter from the usb to take a phone sd card. That way anything that was on your phone saved as an mp3 will play in the car. He suggested the easiest way to get around it would be to be a thumb drive and use itunes or torrents to download music on a thumb drive and just plug that into the usb port. That's exactly what I'll be doing. Tip. 8gb is about 1200 songs.

Galaxy S2 with 2.3.6 does not work
 

I appreciate any help anyone can offer. I have a 2012 Honda Civic LX, and a Samsung Galaxy S2 running Android 2.3.6.

The phone's folders are immediately visible on any computer. I can write to them, read from them, delete, everything from any computer.

The Honda's USB port sees music and graphics on thumb drives and on a Garmin GPS. It also sees music on iPhones. But it doesn't see anything on the Samsung Galaxy S2. The Samsung knows it's plugged into a USB port, because I get a USB symbol on the upper left. But the Honda's iMID doesn't show that there is something plugged into USB. (By the way, USB debugging is turned off.)

Any ideas? Thanks in advance.

Has anyone figured this out yet? I've got a 2012 Civic LX (I'm guessing Bluetooth was on the EX I haven't tried). I'm using my old old old iPhone 3GS in my car via USB right now, but it's nice because I can listen to my iTunes, my music I compose on Soundcloud, Pandora, etc. I'm looking at upgrading through AT&T to a new Samsung Galaxy Note phone though because I enjoy doing digital art and it's the only phone out there with a Wacom active digitizer, which is something I've always wanted. This issue is kind of a deal breaker for me though I don't want to have to resort to plugging into Aux if I can help it or buying an aftermarket bluetooth connection (plus I like being able to charge my phone via USB b/c I'm on the go a lot).