Stock kernel: http://n0rp.chemlab.org/android/nexu...ter-signed.zip
Tweaked kernel: http://n0rp.chemlab.org/android/nexu...l34-signed.zip
Flash in recovery. Adds Busybox and Superuser. The tweaked kernel version uses 2.6.34 with Pershoots CPU and audio settings (not overclocked by default) and an extra patch from San Mehat @ Google to improve DM-crypt performance for A2SD.
You need to reflash your recovery with Clockwork or Amon first if you installed from the OTA.