The tool for extracting iPod firmware is called extract2g. Extract2g can be found on the Linux4nano SVN at http://svn.gna.org/viewcvs/linux4nano/trunk/tools/extract2g/. The Windows binary is provided, and the Linux version can be built with a simple make command. Extract2g supports all of the Nanos (6G Classic?) as of Feb. 2009.
To obtain a list of availible files, type in:
extract2g -l dump.img
Please note that "dump.img" can be replaced with whatever your dump file is named. To actually extract the firmwares, type in:
extract2g -A dump.img
You should now have 3 files:
These are your extracted firmware images. To learn more about these, please visit the Firmware page. If you need more information about using extract2g, type in:
extract2g - -help