This is how I got alsa working on piCore 8 :
tce-load -wi alsa.tcz
tce-load -wi alsa-utils.tcz
sudo mkdir -p /var/lib/alsa
sudo echo "var/lib/alsa" >> /opt/.filetool.lst
Then use "sudo alsamixer" to make adjustments.
Then store it with:
sudo alsactl store
And I had to use this command in bootlocal.sh to restore the alsa settings at boot:
for i in $(seq 1 30); do alsactl restore && break || sleep 0.1; done
If you just run "alsactl restore" then chances are that your USB soundcard isn't ready yet when the restore command in executed.
This extended command will try for 3 seconds to restore the settings.