I spent some time with this over the last couple days. My initial observations:
The code appears to be very similar to previous code (specifically the S90). As this is probably the newest camera ported, that is good news.
The firmware appears to use a new FI2 key. I need to test this to confirm the new key.
When examining the startup code for initialing the MCR registers, it appears that 128 MB is allocated to the raw image buffers, opposed to 64 MB for the S90, having the same number of MP. I suspect this is due to the in-camera HDR, needing to buffer three shots in RAM prior to the HDR.
The executable code section of the firmware is about 12% larger than the S90.