Samsung Galaxy Watch4 R870ZCU1IYH1
SM-R870 1 country Wear OS 6

Samsung Galaxy Watch4 R870ZCU1IYH1 Firmware

Samsung Galaxy Watch4 R870ZCU1IYH1 is an Wear OS 6 firmware for China (CHC). It is the same firmware configured per region and carrier (CSC). Find your country below, verify the file and download for free. Compared with the previous build R870XXU1IYCD: security patch 2025-08-01 instead of 2025-03-01. A newer build for SM-R870 is available: R870XXS2JZG3.

8.8/10 (23)107 times
Wear OS 6
OS Version
2025-08-28
Build Date
2025-08-01
Security patch
1
Countries
1
CSC codes
1
Bootloader binary

Bootloader binary 1. Flashing firmware with a lower binary is usually blocked by Samsung anti-rollback.

Newer builds of Samsung Galaxy Watch4 use bootloader binary 2 (latest: R870XXS2JZG3). If your device already runs binary 2, this build cannot be flashed.

All regional downloads

Pick your region (CSC) to download the matching firmware package.

Paste your current build number from Settings > About phone (About tablet) > Software information, or the output of *#1234#.
    MODEM/CP Version: R870ZCU1IYH1
    ModelRegionCSC VersionRelease dateSizeFile nameDownload
    SM-R870
    CHC China
    		R870CHC1IYH1 2025-08-28 2.939 GiB
    SM-R870_3_20250828143610_6m6e9dsjep_fac.zip

    No matching downloads

    Device specifications

    • Launched withWear OS
    • Display diagonal3.56 cm (1.4")
    • Display technologyOLED
    • Display resolution450 x 450 pixels
    • Processor frequency1180 MHz
    • RAM1500 MB
    • Flash memory16 GB
    • Battery capacity361 mAh
    • Weight30.3 g
    • Band colourBlack

    What's new in R870ZCU1IYH1

    • Stability and reliability
    Device behavior has been improved.
    • Security
    The device is protected with improved security.

    These changes may vary depending on the model, country, or network operator of the customer environment.

    How to flash R870ZCU1IYH1

    • R870ZCU1IYH1 has bootloader binary 1. Your device must run binary 1 or lower: it is the 5th character from the end of your current build number.
    • CSC: Use CSC for a clean install, to change the region (CSC code), to downgrade or to repair a device that does not boot.
    • HOME_CSC: Use HOME_CSC to update the same model and region while keeping your data. Back up anyway: a failed update can still require a reset.
    • The Download Mode key combo depends on the model: see all combos.
    Full flashing guide
    Beware: Manually flashing firmwares may brick your device. Use it at your own risk and follow our tutorial steps.

    Frequently Asked Questions

    R870ZCU1IYH1 is Wear OS 6 firmware for Samsung Galaxy Watch4, released for China (CHC). It includes the 2025-08-01 security patch. Samsung built it on 2025-08-28.

    No. A newer build for SM-R870 is available: R870XXS2JZG3. Install it instead of R870ZCU1IYH1 unless you need this exact version. The previous build was R870XXU1IYCD.

    Download the package for your region (CSC) and unzip it. In Odin, load each file into the slot with the same name: BL, AP, CP (if the package has one) and CSC, or HOME_CSC to keep your data. Odin checks the built-in checksum of every .tar.md5 file before flashing. The download is 2.939 GiB; keep about twice that free on the computer to unzip it. The Samsung Galaxy Watch4 must be on bootloader binary 1 or lower.

    This build uses bootloader binary 1. It can be flashed on a Samsung Galaxy Watch4 running binary 1 or lower; if the device already has a higher binary, Odin stops with "SW REV CHECK FAIL". 30 other builds of this model use the same binary, so you can switch between them in both directions.

    Other builds and changelog for Samsung Galaxy Watch4

    • Security
    The device is protected with improved security.

    These changes may vary depending on the model, country, or network operator of the customer environment.

    • Security
    The device is protected with improved security.

    These changes may vary depending on the model, country, or network operator of the customer environment.

    • Security
    The device is protected with improved security.

    These changes may vary depending on the model, country, or network operator of the customer environment.

    • Security
    The device is protected with improved security.

    These changes may vary depending on the model, country, or network operator of the customer environment.

    • Stability and reliability
    Device behavior has been improved.
    • Security
    The device is protected with improved security.

    These changes may vary depending on the model, country, or network operator of the customer environment.

    Show 15 older builds

    • Stability and reliability
    Device behavior has been improved.

    These changes may vary depending on the model, country, or network operator of the customer environment.

    • Stability and reliability
    Device behavior has been improved.

    These changes may vary depending on the model, country, or network operator of the customer environment.

    • Stability and reliability
    Device behavior has been improved.
    • Security
    The device is protected with improved security.

    These changes may vary depending on the model, country, or network operator of the customer environment.

    One UI 8 Watch Upgrade
    Get things done

    Stay on top of important tasks with the Now bar
    Check the information you need right now and start essential features straight from your watch face. Ongoing tasks will appear in the Now bar at the bottom of your watch face so you can check key information quickly.

    Do more with double pinch
    Just pinch your thumb and index finger together twice to scroll through notifications, control music, take pictures, and more. You can also customize what happens wh...

    One UI 8 Watch Upgrade
    Get things done

    Stay on top of important tasks with the Now bar
    Check the information you need right now and start essential features straight from your watch face. Ongoing tasks will appear in the Now bar at the bottom of your watch face so you can check key information quickly.

    Do more with double pinch
    Just pinch your thumb and index finger together twice to scroll through notifications, control music, take pictures, and more. You can also customize what happens wh...

    • Stability and reliability
    Device behavior has been improved.

    These changes may vary depending on the model, country, or network operator of the customer environment.

    • Stability and reliability
    Device behavior has been improved.

    These changes may vary depending on the model, country, or network operator of the customer environment.

    • Stability and reliability
    Device behavior has been improved.
    • Security
    The device is protected with improved security.

    These changes may vary depending on the model, country, or network operator of the customer environment.

    • Stability and reliability
    The stability has been improved.
    • Security
    The device is protected with improved security.

    • Stability and reliability
    The stability has been improved.
    • Security
    The device is protected with improved security.

    One UI 6 Watch Upgrade
    A new look for your watch

    Discover new watch faces
    Express your individual style with these new premium watch faces. Spatial Number provides an analog clock on top of large bold digits. Simple Digital is for people who prefer a minimalist design. Ultra Info Board lets you quickly check your workout information. You can find these watch faces in the new featured watch faces section of the Galaxy Wearable app. You can also browse watch faces by keyword including colors,...

    One UI 6 Watch Upgrade
    A new look for your watch

    Discover new watch faces
    Express your individual style with these new premium watch faces. Spatial Number provides an analog clock on top of large bold digits. Simple Digital is for people who prefer a minimalist design. Ultra Info Board lets you quickly check your workout information. You can find these watch faces in the new featured watch faces section of the Galaxy Wearable app. You can also browse watch faces by keyword including colors,...

    • Workout Tracker Support
    By connecting your Galaxy Watch to your Samsung TV, you can view workout data from your watch on your TV screen.
    ※ Supported products and connection requirements
    . Supports Samsung TV/Smart Monitor/Projector/Life Style products that are newly released from 2024. However, this may vary depending on Samsung policy.
    . It is supported on the condition that the same Samsung account is registered on both the Samsung TV and the Galaxy Watch.
    . For more information, please v...

    • Stability and reliability
    The stability has been improved.

    • Stability and reliability
    The stability has been improved.

    Model firmware by region