[Amazon Fire Phone] jdmillard:
I've been using this ROM on the Fire phone for a few weeks now. Overall, A+!

Here is some feedback. I hope this is constructive. These observations were consistent on 3 separate Fire Phones (mine, my wife's, and my brother's ... all on this CM ROM build). So these are not random hardware anomalies.

1. When doing video calls (specifically Google Hangouts video calls), the mic/speaker combo of the Fire Phone causes echoes on the other end of the call. The person on the other end consistently (very consistently) hears their own voice with a delay. This only affects the other end of the call - the one holding the Fire Phone won't notice a thing. I've done many video calls to many other devices and different types of devices and this happens every time. The common denominator is the CM Fire Phone. I suspect that that this problem could be solved with some DSP tweaks on the software side.

(Disclaimer: I haven't tried other video chat clients such as Skype. Perhaps someone else run a few tests see if this is an isolated Hangouts issue or a DSP issue).

2. The compass seems to work fine, but only when lying flat. The issue appears that the rotational axis dimensions are inverted. You kinda need to see this to know what I'm talking about. Set the phone on a flat surface pointing north and observe normal behavior - the needle pointing straight forward. The simplest way to see what I'm talking about is to slowly introduce an incline to the phone like it would be when you naturally hold your phone in front of you (aka keep the "home button end" touching the table, and lift the "power button end" off the table forming a ramp). You'll see that the needle eventually flips 180 degrees in an instant. Now the needle is pointing south, obviously wrong. Now create the reverse ramp so the phone starts to face away from you in an upside-down manner and it will start to behave as expected. The problem is that when you're using your phone as a compass (eg navigation apps) you don't hold it sloping away from you, you ALWAYS have it sloped towards you causing inverted direction that is off by 180 degrees.

Now repeat the whole experiment but start off facing the phone south this time. It behaves fine this time. It continues to point in the proper direction even during the first ramp, then does the 180 switch when you slope the phone away from you. This is much more desirable and normal because you always hold the phone sloped towards you or flat... so no problems. So the compass only works if you tilt it up when facing south and tilt it down when facing north. It turns out that you can visualize a plane through which you can rotate the phone to maintain compass accuracy in all directions, but that plane is not parallel to the ground and it's dependent on orientation (which defeats the purpose of a compass). This made me suspect that perhaps the accelerator is not correctly detecting the "down" direction, creating this "plane" of accuracy, but I did some tests and the it seems to be behaving perfectly. The compass only reliably works when facing south or when the phone is perfectly flat. Some of you probably think this is normal behavior - keep in mind that the amount of angle change I'm describing is quite small and dramatically throws off the direction when holding the phone normally.

Something about the axis is off or inverted. I don't know. I suspect that the compass hardware is working just fine and that something in the software is misinterpreting the data which then gets passed to any app requesting the info (a compass app or a navigation app).

I'm curious to see if any of you out there can duplicate any of these symptoms and add any observations or theories. They might be easy fixes with a little bit of hardware insight and some software changes. Any thoughts?