For some unknown reason last three flights I had no logs recorded. Connect to QGC, select “Analyze tools” and nothing listed.
Arducopter 4.3.4, no major changes since last successfully logged flight (well, was a crash, but just couple of arms snapped, no electronics changes or reprogramming.
FC is Matek F405 MiniTE.
The copter is connected of course, and you do Log Download and Refresh ?
yes, refreshing, same actions as always 
also last week couple of logs failed weirdly with a large number of tiny files showing up in the log download page (and giving error when trying to download them).
Are you able to try with MissionPlanner, or maybe APM Planner ?
MissionPlanner says “no logs to download”.
Also today’s 10 minute flight didn’t log. So something is off with FC
Can you save the parameters to a file and upload that please. It should upload here without going to a fileshare site.
I think that FC has onboard flash so there’s no SD Card to try ejecting and re-inserting 
there’s no sd card, it could store up to 16MB logs before. I’ve flashed the latest 4.3.6 copter, took me a bit of fluffing around, as MissionPlanner refused to flush (no heartbeat), but managed to program with INAV and holding the bootstrap button.
Anyway, with 4.3.6, recalibrated everything, loaded old parameters, went for a test flight - NO LOGS.
something is definitely weird.
parameters file.
Also i am now unable to connect to it via wifi unit from my phone/QGC. Used to connect fine, now not connecting, even though the wifi access point is there. Suspect serial ports messed up ???
hex_10Apr2023.param (18.8 KB)
Depending on which serial port the WIFI is connected to, you would probably have to at least set the baud rate
SERIAL1_BAUD,115 (or maybe even 460)
for example.
Currently the logging is set to
LOG_BACKEND_TYPE,4
as if for flash memory onboard, but some of the specs read like it’s got an SDCard (although maybe "built in??)
so maybe try
LOG_BACKEND_TYPE,1
and see what happens.
You can set LOG_DISARMED,1 to create logs without needing to arm and fly. Set it back to 0 after testing.
ok, so after enabling logging while disarmed and changing serial1 settings it gone mental, started giving me WDG: T44 SL0 FL87 FT3 FAE000ED38 FTP180 FLR804F4B3 and bunch of other messages.
Did the rollback to 4.3.5, then installed 4.3.6 again, reset all parameters to defaults, and re-set up everything.
Now records flight logs. Flies quite “flaky” comparing to “old days” before problem started. And still, not connecting via wifi.
unplugged/plugged back wifi unit, now seems to connect ok. And logs seems to get recorded.
So pretty much back to normality
Thanks for looking into it.