FlexRadio FLEX-6600M firmware v3.10.15

Page 1 | Copyright 2025 FlexRadio, Inc. | SmartSDR v3.10.15 Release Notes SmartSDR™ for Windows v3.10.15 Release Notes October 15, 2025 SmartSDR™ v3.10.15 is a maintenance release for all FLEX-8000 and FLEX-6000 series software-defined radios, and the Maestro™.

This version supersedes all previous versions of SmartSDR v3.x.

SmartSDR v3.10.15 is the final release in the SmartSDR v3 series.

The next major release will be SmartSDR Basic v4, including SmartSDR+ (the feature subscription service).

We highly encourage all FLEX-6000 and FLEX-8000 users to install all SmartSDR Basic v4 releases as they become available, to receive all current and prior bug fixes, along with minor feature enhancements from SmartSDR v2 and v3, at no additional cost.

This document covers changes to client software (SmartSDR for Windows, SmartSDR for the “M” radios, and Maestro).

Changes to clients or utilities produced by 3rd parties are not addressed.

Please consult the SmartSDR ​Software User Guide v3 for details on using features and an optimal operating experience.

Before upgrading, please read all sections marked as IMPORTANT for upgrade prerequisites and other important information.

Failure to follow these instructions may create problems requiring FlexRadio support or service staff assistance.

Important Notice: Starting with SmartSDR v3.10.10, the SmartSDR license installed on your radio must be revalidated by connecting to the License Server.

To complete this process, the radio must be connected to your network with Internet access.

Once the SmartSDR license has been successfully validated, the radio will only need to access the License Server again if you later purchase a SmartSDR+ license subscription.

If your PC or Maestro is connected directly to the radio, it will not have Internet access, and license validation will fail.

If you see a prompt to purchase a new license, do not buy one—this message indicates that the radio cannot reach the License Server.

Important Notice: After upgrading to SmartSDR v3.10.15 firmware on all FLEX-8000 and FLEX-6000 series radios, it is recommended to perform a hardware power cycle (also known as a cold boot).

This process involves shutting down the radio, disconnecting and reconnecting the DC power, and then restarting the radio.

Performing a cold boot helps ensure that the firmware update is fully and correctly installed.

Note: Recent versions of SmartSDR v3 address several critical software defects identified in previous versions of SmartSDR.

After upgrading to SmartSDR v3.10.15, downgrading to previous versions of SmartSDR v3 will result in the recurrence of critical issues resolved in this software release.

Page 2 | Copyright 2025 FlexRadio, Inc. | SmartSDR v3.10.15 Release Notes New Features in SmartSDR v3.10.15 There are no new features in this release of SmartSDR.

SmartSignal is still designated as a beta feature.

Bug Fix Highlights in SmartSDR v3.10.15 Please refer to the SmartSDR v3 Changelog for a complete listing of changes.

SMART-11673

Fixed various CW keying issues introduced in v3.9.

Note: to fix this behavior, changes made in v3.9 to allow the MOX button to cancel CWX macros were reverted.

The following change item has been reverted: SMART-9684 - Selecting MOX during a CWX macro in non-QSK mode now terminates transmitting the remaining CWX macro.

SMART-11733

Fixed issues introduced in v3.10 that caused CW power drops, TUNE/MOX button blinking on/off, and characters continuing after the paddle was released

SMART-11562

Fixed an issue where Monitor-like audio would intermittently interrupt the audio stream during transmit with MON off

SMART-11012

Fixed DAX IQ backwards compatibility issues with 3rd Party applications

SMART-11622

Improved balancing of CW Sidetone levels keyed from various sources.

SMART-11730

Fixed an issue with the TX1/TX2/TX3/ACC TX PTT outputs being in the wrong state. Also related to SMART-11727 SMART-11780 Removed unsupported PA Current Meter on the FLEX-6000 Series Radios

API

SMART-11683

Improved transmit slice switching, causing 'Antenna may not be changed while transmitting' messages, high SWR readings, and interlock errors

SMART-11551

Fixed an issue where VOX could trigger a brief transmission on the incorrect Slice

SMART-11781

Improved reliability of software updates Page 3 | Copyright 2025 FlexRadio, Inc. | SmartSDR v3.10.15 Release Notes Important Release Details There are minimum versions of SmartSDR needed for certain FLEX-6000, FLEX-8000, and Maestro models due to hardware revision levels.

The table below indicates the minimum required version of SmartSDR based on hardware ship dates.

Using the latest version of SmartSDR will prevent any issues you may encounter by running firmware below the minimum version for your radio.

Product Hardware Ship Date Minimum Version Maestro C, FLEX-8400M

FLEX-8600M

• 17-February-2025 3.8.23
• FLEX-8400M, FLEX-8600M 2-January-2025 3.8.21
• FLEX-8400, FLEX-8600 9-October-2024 3.8.19

FLEX-6400, FLEX-6400M,

FLEX-6600, FLEX-6600M

24-March-2023 3.4.23 What to do if the SmartSDR software u​pdate does not finish or the radio’s Power button LED remains illuminated purple after 10 minutes?

If ten (10) minutes have elapsed when the software upgrade indicator is no longer moving and the radio has not rebooted to complete the upgrade, power off the radio by pressing the power button.

If the radio’s power button LED stays illuminated purple or the radio will not shut down when pressing the power button, momentarily remove DC power from the radio to shut it down.

The radio should restart using the power button, and the firmware update should have completed successfully.

What to do if the FLEX-8000/6000 fails to boot after upgrading to SmartSDR 3.10.15: If the radio fails to boot after performing a firmware upgrade, please open a HelpDesk support ticket to get the issue resolved.

Upgrading an M-model Radio Front Panel: If you are upgrading an M-model radio using SmartSDR for Windows, the upgrade will not be applied to the software for the Front Panel (display).

Use the information below to upgrade the front panel.  The radio must first be connected to your network and can access the Internet to download the necessary software to update the front panel.  After the radio firmware updates from your PC, shut down SmartSDR for Windows and connect to your radio using the M-model Front Panel.

The Version Select screen should display SmartSDR v3.10.15, showing a download icon.

Selecting that version will start the final portion of the upgrade process.

For a detailed description of the SmartSDR for Windows software upgrade process, please refer to the SmartSDR Software Users Guide v3 Upgrading the radio firmware over a SmartLink connection is not supported.

Since Internet connections can be inherently unreliable, and it is paramount that the firmware upgrade process proceeds uninterrupted to prevent the FLEX-8000/6000 from becoming inoperable, upgrading the radio firmware is only supported using a LAN or network- connected SmartSDR client.

Page 4 | Copyright 2025 FlexRadio, Inc. | SmartSDR v3.10.15 Release Notes Best Practices for Installing / Uninstalling SmartSDR Best Practices for Installing a New Version of SmartSDR for Windows Always back up your Global, TX (transmit), and Microphone Profiles.

For detailed instructions on exporting your profiles to a file on your PC, refer to the SmartSDR for Windows Software User’s Guide.

It is recommended to export all profiles before upgrading to v3.10.15.

Maintaining a good set of profile exports as backups is always a best practice.

Moving back and forth between different versions of SmartSDR may result in data loss unless you have a backup (export) of your Profiles.

Power cycle the radio before installing a new version of SmartSDR for Windows.

To ensure a seamless upgrade, it is recommended that you power cycle your radio before installing the SmartSDR for Windows software on your PC and updating the radio firmware.

Ensure your Windows operati