I analyzed the contents of two files present in firmware update and found out that the file "Zi8_586.img" of the Zi8 firmware contains the whole partition of Zi8 which holds Arcsoft Media Impression.
So, we're left with the file "Zi8_106.fw" that contains the firmware files of Zi8.
Still finding some clues to decrypt the file.
One more thing is that the Kodak Zi8 may be based on platformOViA (www2.renesas.com/platformovia/en/index.html) as it contains many routines and functions from the system.
Will update with more later.