I have been trying a dual boot configuration with harmattan and nemo on my N9 (1603). I managed to have both systems booting and working, but could never achieve stability in harmattan. I tried the following kernels: bzImage that came with nemo installation (on boot-orig dir), openmode kernel, openmode kernel + l2fix. The only kernel that allowed me to boot harmattan was the l2fix. However, the system had stability problems, with several reboots in sequence. On the other hand, nemo was rock-solid. What kernels are you using for harmattan? Is it running stable?