[Bug] (1.15.0 stable) Holybro Pixhawk 6C cannot change IMU frequency

[HB-SP-P]

Describe the bug

Cannot change the IMU frequency for 6C in 1.15.0 stable by saving the configuration file to an SD card. Was able to do it with 1.14.0 stable.

To Reproduce

Create etc/extras.txs in SD card; in extras.txs, write mavlink start -d /dev/ttyACM0
mavlink stream -d /dev/ttyACM0 -s ATTITUDE_QUATERNION -r 200
mavlink stream -d /dev/ttyACM0 -s HIGHRES_IMU -r 200

Expected behavior

Change the IMU frequency to 200Hz

Screenshot / Media

No response

Flight Log

No response

Software Version

1.15.0 Stable

Flight controller

Holybro Pixhawk 6C

Vehicle type

None

How are the different components wired up (including port information)

No response

Additional context

No response

[bresch]

so mavlink stream -d /dev/ttyACM0 -s ATTITUDE_QUATERNION -r 200 works but not mavlink stream -d /dev/ttyACM0 -s HIGHRES_IMU -r 200 ?