Why would you do this two steps? Do you know what you do?
To get any thirdparty DAC working you first need to disable the internal DAC and then you would need to ensure that the right audio sink is chosen.
What update have you done? OSMC or Debian packages?
Provide some logs if you are not able to fix it with dtparam=audio=off to config.txt, reboot and then reselect the audio sink.
I tried the commands to revert from the previous situation of the sound not working after update. dtparam=audio=off was enough to get the audio working again.
I have OSMC App set as soundcard overlay: hifiberry-digi-overlay and the system audio settings picking ALSA hifiberry and the passthrough as SPDIF. These settings haven’t changed at all.