I purchased a used Easyshare as part of a lot at an estate sale. It has issues. The lens says it is a 30x zoom. It has no identifiable marks other than Kodak easyshare (no model/serial numbers) and the picture properties on my PC say it is a z981. BUT - a z981 has a 26x zoom, not 30x! Now, it has defects like the LCD flickers, particularly if you try Manual Focus, the settings knob is off by 1 degree and the colors seem out of sorts. Is it possible someone tried to repair a z981 with z990 lens, COMS or other parts? If so, how do I know? I thought of reinstalling the firmware, but WHICH ONE?? Hmmm??
A Kodak Z981 has 26X on the side of the lens housing . A MAX Z990 has 30X printed on the side of the lens housing and (with a lens tube) uses 67mm lens threads.
A Kodak Z981 does not have the 'zoom' lever around the shutter button like the MAX Z990. Also, the Z981 has a vertical/horizontal slide type switch just behind the shutter button where the MAX Z990 has an on/off switch. The Z981 has a 72mm optical lens where the MAX Z990 lens is smaller. The MAX Z990 has a 67mm optical lens.
These are two very different cameras - although they do look similar.
Now for your question: Can the components of one of these cameras be used to repair the other?
I'd say, not likely without a lot of modification. As for the firmware: Your guess is as good as anyone's. You can try to make it work but if the circuit board was swapped from one camera to the other, that may be whats causing the issue(s) you now have. There may not be a way to effectively repair the camera without spending more than it's worth.