Mazda offered a retrofit DAB which worked through the USB connection. I had it fitted but it never worked properly. Most of the time it is not even accessible, and when it is the reception is very poor (I have another car with a basic DAB radio and it works much better in the same area).
It is no longer offered for the CX5 as they had so many problems, but if you search on Amazon there is a company in Europe offering a similar unit for about £140. They provide a range of software tweaks for different cars, and 2 of the options apparently work on the CX5.
I got the Mazda unit price refunded although it is still installed in case they come up with a solution.
Since then I found that there is a unit made by Dension available on Amazon. Turns out they supplied the Mazda unit but it is not the same as that on offer. They don't even know much about the Mazda unit.
From what I see elsewhere the bugs are probably in the USB connection rather than the add-on, based on other problems reported.
