I had a HLGRC M-100 (M10 Series) GPS module on UART4, wired to 3.3V and was working totally fine, even showed a few people auto rth landing, etc, etc... 

The next day it just stopped working, and can't for the life of my figure out why.

I was plugging in a USB power bank to get the GPS fix before connecting the XT60, all good. Over my ELRS telem on my TX16S I see the sat count and Lat/Long (15 sats for example), then power on the quad with the XT60, and nothing on the OSD.

On the PC connected to BF configurator it doesn't show the GPS icon anymore, BUT does show me on the map correctly, and flicks between 3D Fix true/false/true/false... Says 9 sats, but none are listed.

Nothing had changed between a working auto rth and the next flight. 

Running BF4.4.1 on a Mamba H743. Tried auto baud, 115200, and 57,600, with and without galileo. All the wires look sound and continuity is fine...

Any ideas? Weird as! Otherwise the quad running fine!

Betaflight / STM32H743 (SH74) 4.4.1 Apr 25 2023 / 06:05:55 (e43d591b2) MSP API: 1.45

# config: YES
# board: manufacturer_id: DIAT, board_name: MAMBAH743

Oh GPS passthrough from the CLI shows a load of data coming in BTW! And serialpasstrhroguh with u-blox configurator works and shows lock and location, etc, etc. Loads of sats!

Based on the way it just stopped working from one flight to the next, I know my following suggestion might sound illogical, but try re-flashing Betaflight 4.4.1 to the FC making sure the "Full chip erase" option is switched on. If nothing else and it still doesn't work afterwards, at least doing that will eliminate any possible corruption in the MCU flash memory of FC. Obviously make sure you save a "diff all" of your current Betaflight settings before you do that.

(16-May-2023, 10:21 PM)SnowLeopardFPV Wrote: Based on the way it just stopped working from one flight to the next, I know my following suggestion might sound illogical, but try re-flashing Betaflight 4.4.1 to the FC making sure the "Full chip erase" option is switched on. If nothing else and it still doesn't work afterwards, at least doing that will eliminate any possible corruption in the MCU flash memory of FC. Obviously make sure you save a "diff all" of your current Betaflight settings before you do that.

Cheers for that SnowLeopard. I did try that, and even 4.4.2 pre release, same issues. I re-soldered the joints at both ends, was going to try another GPS module, but I tried one last thing.... switch UARTs. 

It made sense that maybe on RX was working and not the TX messages (as BF does some config), switch to UART 8, and boom works fine (18 sats inside, these M10 chips are awesome!) So maybe I killed the UART 4 RX pad on the FC?

RTH was and is awesome and glad this is up and running, looking at UCenter now... Fun times!

joshua bardwell said his next 2 videos are about m10 GPS and resolving some issues. I was tuned into his livestream for a few. I didnt hear the exact question the person asked but it was m10 related. I have nothing to add myself but if you dont get it resolved on your own, maybe keep an eye on his youtube for a solution

(16-May-2023, 11:49 PM)gunja99 Wrote: Cheers for that SnowLeopard. I did try that, and even 4.4.2 pre release, same issues. I re-soldered the joints at both ends, was going to try another GPS module, but I tried one last thing.... switch UARTs. 

It made sense that maybe on RX was working and not the TX messages (as BF does some config), switch to UART 8, and boom works fine (18 sats inside, these M10 chips are awesome!) So maybe I killed the UART 4 RX pad on the FC?

Yeah, sounds like you have a dead UART for some reason. At least it turned out to be a reasonably simple fix

(16-May-2023, 11:52 PM)matt0725 Wrote: joshua bardwell said his next 2 videos are about m10 GPS and resolving some issues. I was tuned into his livestream for a few. I didnt hear the exact question the person asked but it was m10 related. I have nothing to add myself but if you dont get it resolved on your own, maybe keep an eye on his youtube for a solution

It's to do with the default baud rate and update frequency of the M10 GPS modules in Betaflight 4.4.x and also how quickly they obtain a 3D fix. iFlight have documented the baud rate / update frequency fix for M10 GPS modules at the link below...

https://iflight-rc.eu/blogs/news/m10-gps...nhancement

MomoBrut also covered the same in one of his recent posts on the forum HERE.

Those issues are already fixed in Betaflight 4.4.5 (which is still on nightly development build cycles and not yet released), so if you are running that version you don't need to worry about using UBLOX u-center to reconfigure the GPS module. Betaflight will do that automatically as long as you have the "Auto Config" setting switched on.

(17-May-2023, 12:31 AM)SnowLeopardFPV Wrote: Yeah, sounds like you have a dead UART for some reason. At least it turned out to be a reasonably simple fix

At least I have 8 UARTS, plenty spare. Wonder what happened there. these things happen I guess! 

I did read about M10 issues, and possible H7 issues with it, and thought was that or a config piece lost. Ahhh well, interesting hobby! Always good the community is helpful!

PS. When I tested GPS rescue on 4.4.1 (both on this, and another quad), it's more or less perfect. Always 2m to the left of launch (seen that in most demo videos I've seen), but in a large launch field not a problem. And the flight and descent is a little "wobbly", but it's good, and it works! I'm sure it'll progress as time goes on, I'm sure can still tune a few of the settings!

GPS modules have had disastrous support in BetFlight for a long time. It is only with the arrival of the new GPS Rescue in 4.4.1 that it starts to be solved, I note that it is starting. So it is not true that 4.5 zulu has something actually solved. Autobaud and autoconfig don't work for a long time, just don't say it out loud so someone doesn't get pissed off. In addition, only fixes for M10, which simply have a new set of commands, are starting to be solved, problems with older GPS modules are not and probably will not be solved at all, the only one currently working reliably is the Matek M8Q (and not always). I know, the truth is hard, but ... The scope of things to solve regarding the GPS module and their configuration is terribly large, it is a problem in itself, not only as part of BF, and the number of people who are able to solve it is minimal.