1. Downloaded cm-10.1-20130110-NIGHTLY-i9100.zip and copied to internal SD. Verified MD5 checksum (32d02b655e8d56c504d58a2c9834ac9b).
2. Reboot into CWM Recovery.
3. Created backup.
4. Flashed cm-10.1-20130110-NIGHTLY-i9100.zip
5. wipe cache partition.