1. Downloaded cm-10.1-20130204-NIGHTLY-i9100.zip and copied to internal SD. Verified MD5 checksum (9f8dc616afafe2269018d64b61ce9340).
2. Reboot into CWM Recovery.
3. Created backup.
4. Flashed cm-10.1-20130204-NIGHTLY-i9100.zip
5. wipe cache partition.