Necuno

The Necuno was a phone-like mobile device exclusively manufactured in Finland. The device was designed with a focus on enhancing security and user privacy by omitting the cellular modem, which prevented its use on conventional mobile phone networks. Instead it offered VOIP via a peer-to-peer encrypted communication platform called Ciphra. Standard cellular connectivity was planned for later versions.
The Necuno was mostly open-source, apart from an isolated firmware blob without access to the main memory, used in the Wi-Fi driver for regulatory reasons. The device used Plasma Mobile by default, but it can run a variety of open-source mobile operating systems. It also had an ethernet port.