>“100% open and auditable from the operating system to the cpu” is the main goal of the Betrusted project: https://betrusted.io/

Hopefully there's a 4G version coming. This seems too good to be true.

The 4G modem is exceedingly unlikely to be audittable. Something like srsUE is not welcome on many telcos networks and requires some decently beefy hardware to run.

It's possible to modify it and add a 4G modem, but that would probably be third-party.

The creators of the project suggest using your phone's hotspot if you need connectivity when not connected to Wi-fi (something I heard in interviews they gave).

Which seems to be an iteration of the Precursor (Mobile, Open Hardware, RISC-V System-on-Chip (SoC) Development Kit) by Bunnie Huang and Sean Cobs

> Part of the purpose of Precursor is to validate the system-on-chip (SoC) design we hope eventually to produce as a custom ASIC for use in future such products. This SoC, which we call "Betrusted-SoC," is meant to be the central pillar of security for devices like Precursor. The version of Betrusted-SoC used in Precursor is based on a Xilinx FPGA and has the following features [...] [1]

As for the person who replied to you requesting LTE: won't happen, there's no completely FOSS stack for LTE. Always there is closed source firmware due to regulations. Oh, that wonderful world of transceivers. If you want FOSS, go wired. Tho it seems Precursor found a way to utilize Wi-Fi with a FOSS stack?

[1] https://www.crowdsupply.com/sutajio-kosagi/precursor