IPod Updater

iPod Updater (also known by its later internal project name, iPod Updater Extreme) was a utility to update or restore an iPod to the latest firmware. With the release of iTunes 7.0, update and restore functionality was merged into iTunes.

Supported iPods
The following table lists the firmware versions supported by each known release of iPod Updater. It does not include updates released on or after 2006, when the latest update of almost all iPods were repackaged into IPSWs ahead of the release of iTunes 7.0.

Observations
iPod Updater 2006-01-10 and 2006-03-23 include a ReadMe.rtf file, presumably included by accident, containing the following:

Mac OS 9	CarbonUSB.h, CarbonUSB.cpp, macos9/CarbonUSB_macos9.cpp

Mac OS X	CarbonUSB.h, macosx/CarbonUSB_osx.cpp, macosx/CarbonUSB_FSCalls.cpp

The macosx/CarbonUSB_MacOSX.c file is outdated–do not use it.

CarbonUSB_DebugLog.cpp is required for both 9 and X if DEBUG_CARBONUSB is set to 1

iPod Reset Utility
iPod Reset Utility (initially iPod shuffle Reset Utility) was a variant of iPod Updater released with specific support for the iPod shuffle (1st generation), later adding support for the iPod shuffle (2nd generation). It was intended to be used as an alternative to iTunes, should it fail to restore an iPod shuffle.

iPod Reset Utility is released for Windows, in addition to PowerPC and Intel 32-bit. It does not run on macOS Catalina or later, which removes support for Intel 32-bit.

Observations
iPod shuffle Reset Utility 1.0 references the then-announced, but not yet released, iPod shuffle (2nd generation), in Icons.plist despite a matching icon not being included. Additionally, a Doxygen  build script is found inside the app's resources. However, it doesn't appear to contain anything interesting.

In version 1.0.0.53 for Windows, strings for non-English localizations in the main iPodshuffleResetUtility.exe refer to "Apple iPod Q98", the device's codename. It is unclear where these localization strings are used, as the UI strings are actually loaded from language-specific  files, not the main executable.

In versions 1.0.3 and later, all variants of the iPod shuffle (2nd generation) have a shared firmware, labelled as firmware identifier 130 (its later revisions are 131 and 133), while the IPSWs for this iPod are unique to each revision.

In version 1.0.4.71 for Windows, the iPod shuffle (2nd generation) DFU mode image is referred to as "S5L8441 Rev.1" in the embedded FirmwareVersions.plist ( PE resource), while the chip itself is labelled S5L844A. It is therefore possible S5L844A is a minor variant of S5L8441.