Co-inciding with the spdif recording code check-in there's been a clean-up of the recording settings, clearing out dead wood in preparation for 3.0.
The 'Channel' setting has never worked for rockbox on the iriver, so until a developer chooses to look at it, you've got the choice of stereo, stereo or stereo.
The sample-rate should now automagically be detected, so there's no longer an option to select it (which never worked anyways).
To be honest I'm not sure about the 16/48 on analog. The auto-detection *may* work for analog too...but I suspect it won't. Can someone confirm?