SGS2 + CM9: Flash Siyah Kernel v4.1.5

Steps:

1. Download latest Siyah zip (for CWM Recovery) - Siyah-s2-v4.1.5-CWM.zip

2. Reboot into CWM Recovery.

3. Create backup.

4. Flash Siyah-s2-v4.1.5-CWM.zip

5. wipe cache partition.
5. advanced > Wipe Dalvik Cache.
6. Reboot.

New Setup:
1. CM9 (20120930 Nightly)
2. Siyah Kernel S2 v4.1.5
3. LPS modem

Checksum

About Phone #1 (Stock CM9 kernel is Linux3.0.32, why the downgrade?)

About Phone #2