Have one of those small Revo minis here and I am trying to activate SD card logging.
Firmware on the board is
https://firmware.ardupilot.org/Plane/stable-4.1.7/revo-mini-i2c/
BRD_ALT_CONFIG is set to 0
LOG_BACKEND_TYPE 1
LOG_BITMASK 65535
LOG_DISARMED1
LOG_FILE_BUFSIZE 16
LOG_FILE_DSRMROT 0
LOG_FILE_MB_FREE 500
LOG_FILE_TIMEOUT 5
LOG_MAV_BUFSIZE 8
LOG_REPLAY 0
Wiring of receiver, GPS on RC input and SSD1306 on Flexi port ok and working.
Using the same SD card adapter as shown and wiring between oplink port and adapter identical to pics in
https://ardupilot.org/plane/docs/common-openpilot-revo-mini.html?highlight=revo%20mini
8 GB SD card is formatted in FAT32. But the card stays empty.
hwdef.dat defines SPI3 with PC10 SCK, PC11 MISO, PC12 MOSI and PB3 CS as showing here
Could someone here please enlighten me.
br KH
Sorry for putting this question here in that way.
Thinking it over again, I suppose, I have to compile an adapted firmware myself. I am here on Debian and compiled software, which is not in the Debian sources or EdgeTX from sources. Normally no problem, But AP is a really big chunk. And at the moment I have no idea, what compile options have to be set, to enable SD card logging from the oplink port.
We’ll see …
Compiling the firmware seems to be working.
But what I got now, is ‘master’, I guess v4.1.7? with revo-mini-i2 settings. I am seeking to get the SD card on oplink port working here.
Any hint, what the next steps would be please …
Think I got it working… 
$ ls -R
.:
APM ‘System Volume Information’
./APM:
LOGS STRG_BAK TERRAIN
./APM/LOGS:
00000001.BIN 00000001.log LASTLOG.TXT
./APM/STRG_BAK:
last_storage_bak STRG0.bak
./APM/TERRAIN:
‘./System Volume Information’:
IndexerVolumeGuid WPSettings.dat
