piCore7.00 beta4 - here hifiberry DAC+ is found. But still it produce a similar error in dmesg (so this error is probably not important):
[code][ 15.295052] snd-rpi-hifiberry-dacplus sound: ASoC: CODEC DAI pcm512x-hifi not registered
[ 15.432086] ...
[code][ 15.295052] snd-rpi-hifiberry-dacplus sound: ASoC: CODEC DAI pcm512x-hifi not registered
[ 15.432086] ...