The BM818 has a built in GNSS, but Nicole Faerber told us on another thread that Purism wouldn’t connect the antenna to the cellular modem’s GNSS, so we don’t have to worry about it.
The Teseo LIV3F GNSS is can be turned off by turning off all three hardware kill switches at the same time.
With the physical buttons you can have:
Wi-Fi on, GNSS on, cellular modem on
Wi-Fi on, GNSS on, cellular modem off
Wi-Fi off, GNSS on, cellular modem on
Wi-Fi off, GNSS off, cellular modem off
The combination that I want most of the time will be:
Wi-Fi off, GNSS off, cellular modem on
but the only way to get that is to turn off the GNSS with software which sends commands over the I2C bus (or by physically disconnecting the antenna).