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Latest Firmware : HT19002 (as of 7/2/23)

How To Update Your 9555:

Run the upgrade installer application:

The application is named “Iridium 9555 Software Upgrade <version> Installer.exe"
This will place the upgrade tool and USB drivers into the C:\Program\Files\Iridium\9555 directory

Connect the handset to the PC using a USB cable

If the handset is being connected to this PC for the first time, or to a USB port that has not been used before, the driver will be installed automatically. If this is the case, wait for Windows to show the "New Hardware Installed" notification before proceeding.
If Windows is unable to automatically locate the USB driver, it can be found at C:\Program Files\Iridium\9555\USB\VCOMPORT

Run the Iridium 9555 Software Upgrade tool

A shortcut to this application should be available in the Start Menu in the Iridium 9555 Software Upgrade folder
The target of the shortcut is C:\Program Files\Iridium\9555\Upgrade_Tool\ Iridium 9555 Software Upgrade <version>.exe

Follow instructions presented by the upgrade tool user interface.

During the upgrade process the handset will display various information on the screen, including “Upgrading...”
At times the handset screen may go completely blank
Do not disconnect the handset or press any keys while the upgrade is in progress
At times the handset may display “Inconsistent firmware. Please run upgrade tool.”
The upgrade process may take 20 minutes or more to complete

Document Name Iridium 9555A - User Manual