So, there it is. I compiled drivers and libraries with mod, which supports not only HDMI, but also USB audio output.
Output mode controlled by property "media.audio.out.mode". values are: codec, hdmi, usb.
For enable USB sound card, copy files to device, and add this to init.sun4i.rc:
# USB Audio insmod /drv/snd-hwdep.ko insmod /drv/snd-rawmidi.ko insmod /drv/snd-usbmidi-lib.ko insmod /drv/snd-usb-audio.ko
After installing drivers (note the order!) and connecting any USB audio card, you'll probably find new devices in /dev/snd.
So, now you can use it with NOVO7. Just set "media.audio.out.mode" to "usb" via init.sun4i.rc.
I do it automatically via Tasker app on AC power ON, and switch back to "codec" on AC power OFF.
Here is the archive with all files.
p.s. Only issue i found is poor performance with connected 3G Modem at the same time, but it's related to Allwinners USB host kernel implementation itself.
p.p.s. Fogot to mention libs are for 2.3.4 firmwares, based on released source, IE 2.0.3. Tested with Feiyu MOD from 25th January.
Edited by tsynik, 08 February 2012 - 07:45 PM.