After upgrading to 4.0.0 release, my i2c HMC5883 compass module no longer works, although it is prudently detected by AC. Trying to calibrate it in MP just doesn’t do anything; green bar won’t even appear.
Message log shows repeated ‘Compass not healthy’ messages too.
With ArduCopter 3.6.12 the compass works without problems.
OK, thanks for the report and I’ve added it to our 4.0.0 issues list. I suspect we’ve disabled the driver for the Kakutef7-aio but we will need to check and hopefully we can sort it out.