Hi Janis,
The limitation with 384khz is at kernel level. The Raspberry Pi kernel only supports 192khz max at this time: JustBoom DAC HAT for the Raspberry Pi — Pi Supply
Please note that due to Linux driver restrictions, max frequency is limited to 192kHz on the Raspberry Pi
I did try and implement 384khz myself, but failed to follow the gravy train. I’am not too knowledged with the kernel source code, so, unfortunately, we’d have to wait for RPi devs to make the change.
Another user attempting to push 384khz to kernel source code: Enable 352k8 and 384k sample rates for I2S connected boards/HATs that support those rates by clivem · Pull Request #1460 · raspberrypi/linux · GitHub
The Odroid’s kernel support 384khz, however, we currently experience half playback speed in MPD. This could be an issue with the MPD we compiled, but not sure at the moment. Will need to take another look.