There's a big list of labels used for commands and variables somewhere inside the file, if you look with an hex editor.
Among the weirdest I found are the commands/variables names bellow...
Could this be enough to confirm an iPod phone based on the iPod OS?
These are definitely not from the Motorola phones, as they are running a completely different OS. These are also not from the contact and address lists features that can contain phone numbers.
Now if it weren't enough, look what I found too, just after the phone references:
Can anyone explain what these do in the middle of the main iPod feature/apps list?
A messenger application to go with the phones I guess?
The following are presumably games that were not included. (found among other included games)
Maybe Stacker is a Tetris clone?
I wonder what a search feature could do on an iPod...
Changing the main menu font could be a feature?
A long list of seemingly included fonts can be found elsewhere.
There is a few reference to a graphic EQ that would be enabled by some accessory.
I concluded that it was for the iPod Hi-Fi speakers.
Now is this thing about AppleTalk? Or an instant messenger?
A keyboard for the iPod? For the messenger app?
A choice of multiple graphical appearances?
A way to put a picture in the background of menus?
Maybe a way to set a startup photo?
There seem to be a hidden built-in photo folder in the iPods that's used for retail demos. Anyone knows how to access it?
The next one is a variable name, I guess that it could enable a wider range of movie formats to play on the iPod Video. (Maybe enable all .mp4 and .h264 to play even if they're not pre-scaled to 320x240?)
I also saw many references to a brightness and contrast features, and ways to display and operate the iPod video LCD menu on the TV like Jobs did on stage at Macworld.
Among this list of variable and command name is this Boolean variable:
I guess that if this variable was set to true, some of the hidden features would be activated. Maybe we could even access the prototype Phone mock-up application?
(Edit: Oops, I forgot the M in Firmware in the title)