As far as I understand Ubuntu Touch is basically open source. But is it completely open source? Are all the drivers open source? Are there any binary blobs?
I guess my actual question is: Can I use Ubuntu Touch without running anything that is closed source?
If I recall correctly, on Android (even though Android per se is open source) you couldn't really use it as a phone unless you install some closed source qualcomm services (or something along the lines of that). So I always assumed that the drivers for the baseband related components would be closed source.
But then I read that Ubuntu Touch can only support devices that have an open source device tree. I'm still not entirely sure what that means in terms of being able to write drivers for the device, though.
Does this mean that we actually don't need to use any closed source drivers to get gsm, 3g etc working?
My device for instance (OnePlus One) has an open source device tree, which can be found here. But if you look closely you find things like that: WCNSS_qcom_wlan_nv.bin which make me wonder how open source it actually is.
Ubuntu Touch usually runs inside an android container to access its drivers, which usually also contains proprietary blobs. There is currently no phone available with completely free drivers, so the only way to fix this is by doing a lot of reverse-engineering for every single phone.
Apart from the drivers, the OS itself (as it is distributed by UBports) is completely free and open-source software. On the devices that were sold by BQ and Meizu, there were licensed proprietary bits, like the Nokia HERE AGPS, that UBports replaced with the Mozilla Location Service.
If you're asking about the OS itself, yes it's completely open source. Can it use proprietary? Yes, it can use proprietary drivers (or software in general) because the usage itself of non-open source doesn't hurt the free software definition by Stallman and his "four freedoms", which is:
Free software licence (GPL i.e) grants commercial usage like producing and using proprietary software, the licensing depends only on the used libraries and software components and not on the underlying platform, so if a tool or a driver doesn't use those, is allowed to charge fee even if its underlying in i.e. Ubuntu Touch.