Indeed it got overwritten on the update! My "5.4.0-42-generic" also started to freeze.
Because before (and now again after the update) the "sof-cfl.ri" was just a symbolic link to "sof-cnl.ri" which is a symbolic link to "signed/sof-cnl-signed-intel.ri".
I put the new "sof-cfl.ri" now and "5.4.0-45-generic" is not freezing.
Indeed it got overwritten on the update! My "5.4.0-42-generic" also started to freeze.
Because before (and now again after the update) the "sof-cfl.ri" was just a symbolic link to "sof-cnl.ri" which is a symbolic link to "signed/ sof-cnl- signed- intel.ri" .
I put the new "sof-cfl.ri" now and "5.4.0-45-generic" is not freezing.