Issues with M10 GPS via CAN Bus

Hi,
I’ve been having flakiness issues with the GPS on a M10-l4-3100 module that I have connected to a LUX H7 board via CAN, sometimes I get 20 Sats other times nothin. I contacted Matek and they recommend I try

https://firmware.ardupilot.org/AP_Periph/latest/MatekL431-GPS/

which appears to be a small pre-compiled module. My question is how to I load this with 4.3.0?

Thank you!

Update: I found the mechanism for updating the device, very cool but a bit buried, I had completely misunderstood what I was looking at. Sadly it didn’t help, I think my module is a bit dodgy, won’t be dusting off with it anytime soon.

This has been brought up in the Developer meeting
Probably make sure you set GPS_GNSS_MODE to the minimum number of constellations that work reliably for you, no more than two.

Or try Master V4.4.0-dev as a fix has been merged. You may not want to fly on Master but it could give you an indication that it is indeed the problem.

Another Update: I’ve tried the new AP_GPS firmware & 4.4.0, not much has changed except that now I max out at about 9 sats with crappy HDOP. I’ve got a another model sitting right next to it with an M9-5883 (serial), Lux H7 running 4.3.0 that gets HDOP under 1 in 1:40. I believe this is a hardware problem (with this particular unit) that only a new one will solve. Thank you!

It will likely get attention soon as there is a Dev proposal to acquire a couple of these and do some fast auto mission work with them.

Yet another exciting update:

This information was provided by Matek support.

desolder these 2 resistors to disconnect UART connection between M10 module and STM32L431 MCU

Catch012C

then connect RXD TXD G 5V to a USB-TTL adapter. connact M10 module to u-center

Catch5FF1

After doing this, solder back that 2 resistors, or bridge the resistor pads with a drop of tin.

Matek_Service

This is nice information because it allows one to talk to the M10 directly with the ublox center software. I’m pretty sure the unit I have is defective and I’ve replaced it with an M9N-5883 but the M10-L4-3100 is a pretty cool, inexpensive CAN bus solution (3 peripherals with 4 wires) if it worked.

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Same here. received the Mateksys M10-L4-3100 few days ago. Connected to FC Matek H743 Wing v3 and the FC Matek H743 slim V3 . Both still on the bench and loaded with FW ArduPlane. No GPS -Fix yet with both FC. All other older GPS units connected to a Cube -orange and also a Pixracer are having excellent fix in the same environment. I am pleased I found your explanation here and will follow closely your topic. There is definitely something wrong with the M10-L4-3100 I have here.

Is anybody around who purchased that M10 L4-3100 and has it working fine?

I think Matek are going to send me one

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Thanks Andy.
BTW - I did comment to you at YouTube yesterday.