If you run the alsa_amixer it will tell you a bunch of things.
On my USB adapter there is the playback path, the record path and the record monitor path.
Each of them has a switch to turn on and a volume.
You can play with these values in alsa_amixer.
Right now, I only have Noogie and a Windows machine.
I can't mount the other partitions or access the files.
If I were to get in the habit of bricking my Nook I'd look for a better solution.
On my Nook right now you still just have the selections of 8K or 16K,
however, it records in stereo (from a mono source) at 44100 using either setting.
Such behavior cause data overruns in Skype.
@zholy, I have no idea why your USB buttons are not working, look at dmesg and logcat.