Boot Rattle with capital R

Hi all, I thought this was worth sharing..

I had been having a boot rattle on the pax side of my CX-5. LOUD. Only while driving over rough roads. squeak-rattle-squeak-rattle.
Of course I emptied out the trunk and tried everything else on the forum and each time after messing around it would be gone for a while but always come back. Especially on long drives. I finally took it to the Mazda dealer, it was due for a service, and they had a look. They said they thought they'd fixed it and for three days it was quiet as a mouse. Then. It was back.
This time I had a bit of an epiphany. After prodding all the plastics in the rear to replicate the rattle, without success, I started picking away at the black circular covers on the top of the boot lid (on the inside). As it turns out you can remove these quite easily with your fingernails. Behind them are the nuts that hold on the plastic "spoiler". At least, I think that is what they do.(2thumbs)
The nut was lying loose behind the plastic cover. Rattle=loose nut. squeak=Plastic spoiler moving around. (probably)
There is no friction washer behind the bolt, so I guess on our rough roads they vibrate loose over time. (the other nut was loose as well but still on the bolt).
I bought some tube wrenches and tightened them with some silicone based glue. Quiet bliss.
A friction washer might have been better (why are they not installed) but glue does the same job.(yippy)

Might be worth to check those nuts for tightness, even without a rattle. I do not know if those are the only two bolts holding on the "spoiler", but better save than sorry.
I think this solved my rattle, but I wont be able to tell for sure till driving it for a few weeks.

Cheers
Now the speaker cover "buzz" on the front dash...

I went through the same detective work and discovery. Definitely a metallic/squeaky noise. After trying all the other remedies from other posts (thank you) I sat in the cargo area while my wife drove and I was SURE it was something behind one of the 3 inside plastic panel covers which go above and around the rear window. So I removed them. The rattle returned. Out of desperation I closed the hatch when we got home and began tapping the outer area (the spoiler) and I heard the squeak on the left side of the spoiler. I could identify that squeak with my eyes closed. The left spoiler nut wasn't even finger tight. They should have at least used some lock-tite. Mine sounded like the pass side too while driving but it was definitely the left spoiler nut in my case. Am now slowly adding back all the tools, panel covers, etc. that I removed trying to find the source. My wife is still not convinced but she will be in a day or two.

Here's a tsb: http://mazda.oemdtc.com/562/rattle-noise-from-rear-of-vehicle-2015-mazda-cx-5