Hello everyone!
Just put this head unit in my car today. Luckily I'm not having most of the issues here. however "everytime I select the pandora option, I have to acknowledge the access key request that pops up on the phone, but after that it'll work great until I turn off the stereo or car engine (I'll have to redo it again when I turn the ignition)." is happening to me. I've got a droid 4 rooted stock. I'm gonna try my CM10 rom (which I can't use as a daily driver due to other issues in the rom), and I'm gonna try a few other device (N7 stock, D3 stock and CM10 / 9, D1 CM7, stratosphere whatever's on it).
Hopefully I can figure out where the blame lies (motorola or alpine). I might have to dive in to the bluetooth spec to see what the behavior is supposed to be. What is actually causing the issue is that the head unit switches passkeys every time it starts. If it keeps the same passkey, I don't think there will be any problems.
edit: some quick research (before testing) found this:
http://mclean-linsky.net/joel/cv/Simple Pairing_WP_V10r00.pdf
It looks like devices are only supposed to generate the passkey when pairing, and not during every connection. This seems obvious, due to the security risks associated with generating a new key every connect. I'm hoping that by finding out which device doesn't comply with bluetooth standards, we can force the manufacturer to release an update (or lose their bluetooth certification). Otherwise, I doubt anything will be done to fix this.
edit 2: OK, I did some testing. Verdit: bugs abound. My nexus 7 worked fairly well, and reconnected automatically after power cycling the car, so this leads me to believe that the head unit is complying with the spec (unless android has a hack to get this sort of thing to work). The droid 3 was pretty much the same as the D4 stock. The custom rom didn't really support bluetooth. I also tested an HP touchpad, which couldn't connect to pandora (it's running a really old CM9 version, so understandable that it doesn't have good bluetooth support). The droid 4, I tried a few custom roms: the latest CM10 build from hashcode, which didn't work for pandora (can't remember audio though), the december 17th CM10.1 build, which couldn't even turn on bluetooth, and lastly, the 1-16 build of CM10.1 (ooh, two newer builds, I'll try the latest tomorrow), which worked flawlessly! (well, the bluetooth did. Every time I recieve a call, phone crashes, rings forever, and I have to hard boot the phone. unfortunately, this is a bigger issue than the bluetooth one, so I'm stuck on stock until this is fixed. I'm contacting hashcode to see what I can do).
I have not yet tested the stratosphere and the droid 1 (they were dead). I think the stratosphere will be the most telling: if it works, it's a motorola issue. If not, it's something alpine might want to fix.
I also found a few bugs on the Alpine side though. First, when trying to 'clear' (which is actually unpair) a device, the head unit seems to need to connect to the device first. That's a problem if you already removed the pairing on a target device. I had to reset my radio to get rid of the device. Second, when a bluetooth device tries to connect to the radio while the radio is connected to a different device, the connecting device will give a passkey error (the head unit is probably trying to use the passkey of connected phone). Alpine should either disable discovery during this time (and make sure searching works) or fix it to be able to handle two passkeys simultaneously. The former seems much easier. Third, after a reset, the radio takes a while to start up. However, it finishes loading the main screen and the first level of menus before it's actually done. When I went into the main menu, I couldn't actually click on anything until it finished booting. I thought my knob was malfunctioning.