Hi,
I installed Release 4 RC2 on the Kakute F7 mini board. The ship flies nicely but logging is not working.*I I get these errors on the HUD:
Then trying to download logs , the following error is displayed:
The log parameters are as follows:
Any idea what I’m doing wrong or is this an issue with the F7 mini (Kakute) ?
You need backend type 4
Ah ? What is backend type 4 ?
I think @andyp1per is referring to the LOG_BACKEND_TYPE param.
https://ardupilot.org/copter/docs/parameters.html#log-backend-type-ap-logger-backend-storage-type
It appears to be set to 3 in your screenshot. looks like the description in mission planner is not complete or out of date. It appears to be mission option 4.
It’s block logging. If you select only that option checkbox you will see it change to 4.
Ok I’ll give it a try with 4. Thanks
Logging on these F4/F7 boards w/o an Sdcard seems to be a bit fiddly but I have generally had good luck with an Omni F4 Nano.
Yes it’s a bitmask, so you need bit 3 for block logging (type 4) enabled.
What I don’t get is that this is supposed to be set by default from hwdef.dat, and the logic is in there - it just isn’t working. I experienced the same thing. I was planning to try and debug it, but it involves completely wiping and reflashing from the bootloader up.
The logic I am referring to is that the backend type default is HAL_LOGGING_BACKENDS_DEFAULT which if HAL_LOGGING_DATAFLASH is set - which it is in the kakute hwdef.dat - is Backend_Type::BLOCK in AP_Logger.cpp. Maybe something else is unsetting it?
I checked the default backend and it seems to be Block for the KakuteF7Mini so I think it’s defaulting correctly. For the KakuteF7 (non-mini) it’s default to Filesystem which I also think is correct. Does this seem OK or maybe I’m missing something?
By the way I tested this without actually testing on a KakuteF7 but I used “#pragma message …” to display what the default should be during compilation.
@rmackay9 it all seems correct, but I too experienced the backend being set wrong and am not sure why. I thought maybe it was from people who originally flashed with the Kakute FW on their mini and then upgraded - but given that the bootloader ids are different now I’m not sure that explains it. It’s a mystery! 
FWIW the experiement I was going to try was wiping and reflashing the whole thing including bootloader using the betaflight configurator. That’s generally how these boards start life with ardupilot so if that works then I think it works to all intents and purposes.
My logging hardening fix has been merged to master. I think this fixes a lot of the flash based logging problems, but the code is quite fragile so there could easily be more. https://github.com/ArduPilot/ardupilot/pull/13130
