The firmware installer for Iridium 9555 HT19002, along with the release notes may be downloaded below.
Note: There have been many 9555 hardware revisions over the years, not all of which have been listed in the release notes (under 'Hardware Compatibility'). All revisions up to the release of the firmware update should function properly.
The HT19002 release notes contain steps that should be used to upgrade an Iridium 9555 handset from firmware version HT11001 or later.
How to check current Firmware:
Before updating the Firmware on your Iridium 9555 it's important to know what firmware version your phone currently has installed. To check the current version:
1. On the main screen, select Menu
2. Scroll down and select Setup
3. Scroll down and select Phone Information
4. The Firmware Version will be the first option
Firmware update files: