Amazfit is rolling out a new firmware update version 3.3.6.1, bringing a much-anticipated feature to the Amazfit Helio Strap: dedicated tennis tracking. This means racket sport enthusiasts can finally log their sessions accurately with the screenless fitness band. Beyond the court, the update also delivers significant under-the-hood enhancements, including vital optimizations for the BioCharge energy algorithm, more reliable nighttime heart rate measurements, and various other essential bug fixes to boost the wristband’s overall performance.
Expanding Sports Support

Since its launch in June, the Amazfit Helio Strap has carved out a niche among sports-focused users seeking a minimal, high-performance tracking device. However, a significant point of contention was its initial limitation to only 27 supported sports. This paled in comparison to the extensive library of 177 activities available on some of Amazfit’s flagship smartwatches, such as the T-Rex 3. Unsurprisingly, the community voiced strong demand for more sports, with ball and racket games—especially tennis—being at the top of the request list. The new firmware update 3.3.6.1 addresses this directly, integrating a full Tennis Mode within the Zepp Health app, alongside several other user interface (UI) enhancements.
Precision Tracking for Racket Sports
Before this update, tracking tennis practice with the Helio Strap was a somewhat hit-or-miss affair, relying on approximations of similar activities. With the new, dedicated mode, users can now properly monitor their training sessions. The device leverages heart rate data to accurately assess and calculate workout intensity. This crucial information is then presented clearly and visually within the user’s workout profile on the Zepp app, providing a much richer and more accurate insight into the exertion of their tennis play.
BioCharge Algorithm Refinements
The update also focuses on enhancing the BioCharge algorithm. This feature is Amazfit’s equivalent of Garmin’s Body Battery, designed to gauge a user’s overall energy levels by analyzing factors like stress and sleep quality. While previous iterations of BioCharge haven’t always delivered on their theoretical promise, the latest algorithm aims to rectify common user complaints. Specifically, the release notes indicate a fix for the problem of rapid overnight energy depletion and consistently low Wake BioCharge scores, aiming for a more reliable and accurate depiction of the user’s recovery status.
Additional Fixes and Availability
Rounding out the update are several important bug fixes designed to improve the overall accuracy and reliability of the device. These include resolving issues with nighttime heart rate measurements, correcting exaggerated calorie totals recorded during workouts, and eliminating step miscounts that previously occurred during swimming and cycling activities. The entire package is a lightweight 3.4MB update, but users must ensure they have the Zepp app version 9.13.0 installed to access and download the new features.
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