[ex_amazon_sde]

How does this interacts with FLOSS software used on the phone?

This is an example of "tivoization" and should be prevented by GPLv3

[yjftsjthsd-h]

Do any phones use GPLv3 code? Closest that I know of is Linux under v2, but Android generally is permissively licensed.

[zifnab06]

The large majority of Android is Apache 2, rich requires attribution but no release of source code.

[ex_amazon_sde]

There's a good amount of software under GPLv3 on f-droid.