Mostly, but not universally. The January 2026 firmware appears to have repaired the worst One UI 8 Watch failures on many Galaxy Watch4 and Watch4 Classic units, including missing health readings, unreliable wrist detection, Always-On Display (AOD) glitches and abnormal battery drain. Samsung’s changelog only says “device behavior has been improved,” so it never officially confirmed a bug-by-bug fix. If your watch offers a later build, install that instead: Samsung’s SM-R870 history lists newer March and June 2026 releases.
What went wrong after One UI 8 Watch?
The December 22, 2025 One UI 8 Watch update (Wear OS 6, listed by Samsung as AndroidWear 6.0) was followed by reports from Watch4 owners of health sensors failing, wrist detection not recognizing the watch, unreliable sleep and workout tracking, AOD glitches, rapid battery loss and a sluggish interface. Some owners also reported slow or unstable charging, notification failures, connectivity problems and inconsistent double-pinch gestures. The strongest and most consistently reported problems were sensors, wrist detection, AOD, battery drain and performance; the other symptoms were more variable.
Android Authority reported that Samsung interrupted the initial rollout after complaints about sensors, AOD, battery life and lag. SamMobile later reported a corrective update with improvements observed by users. These reports establish real-world symptoms, not a manufacturer-certified fix rate.
Samsung community posts also attributed some sensor and wrist-detection behavior to internal values not being carried over correctly after the upgrade. That is community guidance rather than a verified engineering explanation.
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- Rotating Bezel Navigation: Physical rotating bezel allows precise and intuitive control of apps and menus.
What was the January 2026 firmware?
For the Bluetooth Galaxy Watch4 SM-R870, Samsung released build R870XXU1JYL6 on January 27, 2026, with the January 1, 2026 security patch. Samsung’s official description is simply “Device behavior has been improved.” See the complete model history at Samsung’s Galaxy Watch4 SM-R870 update page.
The same corrective phase covered Watch4 and Watch4 Classic families, but firmware numbers and release dates differ among 40/44mm Watch4 models, 42/46mm Classic models, Bluetooth versions, LTE versions, countries and carriers. An LTE model may wait for carrier approval. Do not treat R870XXU1JYL6 as a universal identifier.
What does the patch appear to fix?
| Problem | What owners and reporting indicate | Confidence |
|---|---|---|
| Heart-rate and other health sensors | Many reports say readings returned after the corrective update. | Moderate to high |
| Wrist detection | Owners reported detection working again or becoming more reliable. | Moderate |
| Always-On Display | Improved for many users, although some still needed to toggle AOD off and on. | Moderate |
| Abnormal battery drain | Many users reported better endurance; no controlled Samsung battery test was published. | Moderate |
| Lag and sluggishness | Reports describe a more responsive interface, but evidence is anecdotal. | Moderate |
| Notifications and gestures | Mixed reports; Samsung did not identify these as specific repairs. | Low to moderate |
| Charging behavior | Reported by some owners, but not clearly documented as fixed. | Low to moderate |
SamMobile’s report on the update is available at SamMobile. Android Authority documented the rollout and remaining AOD exceptions at Android Authority.
Rank #2
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What Samsung officially confirms—and what it does not
- Official firmware record: Samsung confirms the build, release date, security level and a broad “device behavior” improvement statement.
- Independent reporting: SamMobile and Android Authority describe sensor, battery, AOD and performance improvements reported by users.
- Community evidence: Individual Samsung Members posts help identify symptoms and workarounds, but they are not controlled testing.
- Still unproven: Samsung has not published a list explicitly confirming that heart-rate sensors, AOD, battery life or every other symptom is fixed on every model.
Therefore, “fixed” should mean that your watch again produces readings, detects your wrist, keeps AOD stable, avoids abnormal drain and performs normally—not that every unit has factory-new battery capacity or identical behavior.
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January is no longer the newest SM-R870 software
For SM-R870, Samsung lists these later releases:
| Date | Build | Security patch | Samsung’s description |
|---|---|---|---|
| December 22, 2025 | R870XXU1JYK4 | October 1, 2025 | One UI 8 Watch / Wear OS 6 upgrade |
| January 27, 2026 | R870XXU1JYL6 | January 1, 2026 | Device behavior improved; security |
| March 26, 2026 | R870XXU2JZC2 | February 5, 2026 | Stability and reliability; security |
| June 22, 2026 | R870XXS2JZE1 | May 5, 2026 | Security improvements |
As of August 2026, check for the newest firmware offered to your exact watch rather than stopping deliberately at January. Samsung warns that availability and changes vary by model, country and service provider.
How to install the update
Using Galaxy Wearable
- Open Galaxy Wearable on the paired phone.
- Tap Watch settings.
- Tap Watch software update.
- Tap Download and install.
- Keep the phone and watch close together, sufficiently charged and connected until installation finishes.
Directly on the watch
- Open Settings on the Watch4.
- Tap Software update.
- Connect to the internet if prompted, then download and install the offered build.
Afterward, verify the result at Settings → About watch → Software information. The direct-watch route requires an internet connection.
Rank #3
- Display: 1.2" (30.44mm) Circular Super AMOLED (396x396 pixels). Full Color Always On Display. Corning Gorilla Glass DX.
- Exynos W920 Dual Core 1.18GHz
- Sensor: Accelerometer, Barometer, Gyro Sensor, Geomagnetic Sensor, Light Sensor, Optical Heart Rate Sensor, Electrical heart sensor, Bioelectrical Impedance Analysis Sensor, Hall sensor
- Bluetooth 5.0, Wi-Fi 802.11 a/b/g/n 2.4+5GHz
- Wear OS Powered by Samsung. Compatible with Android 6.0 or higher
How to check whether your watch is actually working again
- Remove and put the watch back on to test wrist detection.
- Run a heart-rate measurement in Samsung Health.
- Start a short workout and confirm live sensor data.
- Check sleep tracking the next morning.
- Enable AOD and test it in normal use.
- Observe battery behavior for at least one full charge cycle; immediate post-update app activity can temporarily increase drain.
- Check notifications, Bluetooth reconnection and charging while the watch is cool and correctly positioned.
If problems remain after updating
AOD is still unreliable
Confirm AOD was not disabled, check power-saving modes and try a different watch face. Toggle AOD off and on; Android Authority reported this helped at least one user. Persistent failure may indicate a software conflict or hardware fault.
Sensors or wrist detection still fail
- Restart the watch.
- Install any later firmware offered for the exact model.
- Update Galaxy Wearable, Samsung Health and watch apps.
- Run available connected-device diagnostics.
- Back up data, then remove and re-add the watch only if necessary.
- Use a factory reset only as a last resort, because it erases local data and requires re-pairing.
- Contact Samsung if sensors remain unavailable after a reset; persistent failure can be physical damage rather than firmware.
Battery life is still poor
Check LTE signal strength, continuous heart-rate or stress monitoring, AOD, GPS-heavy workouts, brightness, notifications and third-party watch faces. A Watch4 launched in 2021, so an aged lithium-ion battery may have lost capacity; software cannot restore worn cells.
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Rollouts differ by model, country and carrier. Bluetooth and LTE versions may not update together, and carrier-branded LTE watches can require approval. Update Galaxy Wearable first and use Samsung’s page for your exact model. Avoid casual manual flashing because a regional mismatch can cause data loss, bootloader problems or warranty complications.
Rank #4
- BODY COMPOSITION ANALYSIS: Galaxy Watch4 is the first smartwatch to off body composition data right on your wrist, On your own schedule, now you can get readings on body fat, skeletal muscle, body water, basal metabolic rate, and Body Mass Index.Supported Application:Heart Rate Monitor,Sleep Monitor,Fitness Tracker. Connectivity technology:LTE,Bluetooth,GPS. Wireless comm standard:Bluetooth
- BETTER SLEEP STARTS HERE: Wake up feeling refreshed and recharged with advanced sleep tracking; When you go to bed, your Galaxy Watch4 sleep tracker starts monitoring your sleep and SpO2 levels continuously
- BE SMART ABOUT YOUR HEART: Take care of your heart with accurate ECG monitoring and keep an eye on possible atrial fibrillation, a common form of irregular heart rhythm; Share personalized readings with your doctor using the Samsung Health Monitor app on your compatible Galaxy phone
- MAKE EVERY WORKOUT COUNT: Get the most out of every exercise session with advanced workout tracking that recognizes 6 popular activities, from running to rowing to swimming, automatically in just 3 minutes; Stay motivated by connecting to live coaching sessions via your smartphone or to dynamic Group Challenges with your friends
- GO THE EXTRA MILE: Improve your runs with advanced running coaching technology; VO2 Max readings assess your oxygen levels to manage and track your heart and lung endurance
Notifications or gestures remain inconsistent
Check Galaxy Wearable notification permissions, phone-side permissions, Do Not Disturb and Modes, app updates and compatibility with the paired phone. Test with Samsung’s default watch face and apps before concluding that the firmware is at fault.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.Should you keep the Watch4 or replace it?
Install the newest offered firmware before deciding. Keeping the watch makes sense when sensors work, battery endurance is acceptable and performance meets your needs. Compare an authorized battery-service quote with replacement cost when the case, display and sensors are sound but the battery is worn. Replacement is more reasonable when the watch remains unreliable after current firmware, has physical or charging damage, or is too slow for your needs.
| Your situation | Practical direction |
|---|---|
| Works normally after updating | Keep the Watch4. |
| Sensors work but battery is badly degraded | Compare battery service with a Galaxy Watch FE or discounted Watch7. |
| Still unreliable on current firmware | Consider replacement or Samsung service. |
| Wants the newest Samsung features | Look at Galaxy Watch8 or Watch8 Classic. |
| Wants a lower-cost Samsung replacement | Consider Galaxy Watch FE. |
| Wants an inexpensive backup | A used Watch4 can work, but require returns and verify battery, model and update eligibility. |
Official product and support pages are Samsung watches, Galaxy Watch FE, Galaxy Watch7 and Samsung Support. Prices, trade-in values and repair estimates change, so check them directly before buying.
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1Repair Windows errors before they cause bigger problems2Fix the driver behind crashes, sound loss and screen glitches3Clear out junk files and repair common Windows errorsVerdict
The January 2026 release was a meaningful corrective update, not a guaranteed clean slate. It appears to have restored core Watch4 functions for many owners affected by One UI 8 Watch, especially sensors, wrist detection, AOD and abnormal drain. Samsung’s nonspecific changelog and mixed reports mean persistent faults must be diagnosed individually. In 2026, install the latest firmware offered for your exact model rather than intentionally stopping at the January build.
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