Garbage NMEA output from GPS

[wibble]

I can't say I'm surprised - I was having trouble without SD, but it's good to have confirmation. SD was just an example of a digital interface that could cause interference, and might be configurable to reduce it. As it happens it looks like they are among the identified interfaces (is wifi/bluetooth on one of them?) It could be they're only configurable via devicetree. There may be other interfaces that have configurable drive strength at the hardware level, but don't expose it in the driver. This is why we need someone with hardware knowledge. If we're unlucky it's an inadequate antenna, poor signal routing, or something noisy that we can't adjust (or slug with caps)

Who knows...most people's eyes would glaze over if I mentioned NMEA ;-)