Updated on June 2, 2026
You can repair your SM-R855U Galaxy Watch3 using the official Samsung Galaxy Watch3 SM-R855U firmware. This page provides all the necessary files and instructions, including tools for hard resets, FRP removal, IMEI repair, and the exact flashing steps.
Device: Samsung Galaxy Watch3 SM-R855U | Chipset: Exynos 9110 (10 nm) Dual-core 1.15 GHz Cortex-A53 | Flash Tool: Odin
Android: Tizen-based wearable OS 5.5 | File Type: .tar.md5 / ZIP (Contains AP, BL, CP, CSC files for Odin)
⚠ Warning: Flashing erases all data. Back up first.
Samsung Galaxy Watch3 SM-R855U Firmware (Flash File) Drivers, Tools & Guide
Installing the Samsung Galaxy Watch3 SM-R855U firmware requires the correct Odin version, official drivers, and the right flash files, all of which are provided here. Using Odin to flash Samsung software is a simple procedure when you understand the process. I have organized the correct firmware package for the Samsung Galaxy Watch3 SM-R855U, the necessary Odin build, and proven instructions right here.
Before you begin, ensure you sign out of any active Samsung accounts on the watch. Skipping this step often triggers Knox security, resulting in a KG lock that takes much longer to resolve. Official Samsung firmware uses the .tar.md5 format. Once you unzip the folder, look for files labeled AP_*, BL_*, CP_*, and CSC_* (or HOME_CSC_*). If these files are missing, you likely downloaded the incorrect package.
The Samsung Galaxy Watch3 SM-R855U firmware downloads as a compressed ZIP archive. You can unpack it using WinRAR or 7-Zip. Once unzipped, verify that the folder contains files such as AP_*.tar.md5, BL_*.tar.md5, CP_*.tar.md5, and CSC_*.tar.md5 (or HOME_CSC_*.tar.md5). Missing these specific files means you probably have the wrong software package for your watch.
Remember that installing stock firmware completely wipes your device data. This factory reset behavior is intentional and helps clear up persistent software glitches like FRP locks, application crashes, severe lag, forgotten security patterns, system freezes, Wi-Fi or Bluetooth drops, excessive battery drain, and soft brick conditions.
Hard Reset Samsung Galaxy Watch3 SM-R855U
A hard reset on the Samsung Galaxy Watch3 SM-R855U is performed by holding the Volume Up and Power buttons together while the device is powered off to access the recovery menu. You can factory reset the Samsung Galaxy Watch3 SM-R855U without a computer by turning the watch off entirely. Next, press and hold Volume Up + Power simultaneously (or Volume Up + Home + Power on older models with a physical home button) until the recovery menu loads. Scroll down to “Wipe Data/Factory Reset” using the volume keys and press the Power button to confirm your choice.
Performing a hard reset wipes all personal data and returns the Samsung Galaxy Watch3 SM-R855U to its original factory settings. This process resolves the majority of software hiccups, including sluggish performance, random app closures, missing screen lock PINs, and continuous bootloops. Should the problem remain after the reset, the Odin flashing tutorial in the next sections will help you install fresh firmware.
Samsung Galaxy Watch3 SM-R855U FRP Bypass
You can bypass FRP on the Samsung Galaxy Watch3 SM-R855U by using a free Android apps launcher to access device settings during the initial setup screen. The most efficient method to bypass FRP on the Samsung Galaxy Watch3 SM-R855U involves using a free Android apps launcher to reach your settings while inside the setup wizard. Following a factory reset or a firmware flash, you might encounter a Google account lock (FRP). You can use our free Android apps launcher to quickly get around this barrier. Removing your Google account before starting the flash is always the best practice because it prevents this lock from activating.
Why Do We Need Samsung Galaxy Watch3 SM-R855U Firmware?
Flashing the Samsung Galaxy Watch3 SM-R855U firmware is necessary to fix deep software issues, update the operating system, or recover a device that will not boot properly. Samsung devices, including the Samsung Galaxy Watch3 SM-R855U, are flashed using the Odin utility regardless of their internal processor. If you are experiencing a boot failure or persistent software glitch, installing the official Samsung Galaxy Watch3 SM-R855U firmware usually corrects the problem:
- Gain access to your watch if it becomes locked or disabled.
- Install the newest Android version supported by your hardware.
- Clear up continuous bootloops, system lag, and screen freezing on your SM-R855U Galaxy Watch3.
- Fix failed over-the-air updates and abnormal battery drain.
- Return the device to its original factory state to maintain your warranty.
- Recover the watch if it only boots into the recovery menu.
- Fix KG lock or Knox errors resulting from an interrupted or incorrect flash.
You can learn more about stock ROMs and why flashing works.
Choosing the Right Firmware Version
Choosing the right firmware version requires matching your exact model number, region code, and binary level to the official software package. Verify that you possess the correct file before starting the installation. Installing the incorrect software is a serious error that is hard to undo:
- Identify Your Exact Model Number: Go to Settings › About Phone and note your full model number (e.g. SM-R855U). The letter suffix matters, U/U1 = USA, W = Canada, N = Korea, B/F = International/Global. Flashing firmware built for a different variant can cause issues.
- Match the CSC (Region): The 3-letter region code in the firmware filename must match your device. Check Settings › About Phone › Software Information for your current CSC, or look at the Service Provider line in Download Mode. Common codes: XAA (US), BTU (UK), INS (India), SER (Russia).
- Check the Binary Level: Look at the version string in your current firmware (e.g.
XXU9BZDP, the number after the letters is the binary level). You cannot downgrade to a lower binary level. If your device is on Binary 9, only flash Binary 9 or higher firmware. - Confirm the Build Date: The last 4 characters of the PDA version encode the build date, first character is the year (A=2024, B=2025, C=2026), second is the month (A=Jan through L=Dec).
- Verify in Download Mode: Power off, hold Volume Down + Power to enter Download Mode. This screen shows your exact model, CSC, and current firmware version, use this to confirm before flashing.
Firmware Details for Samsung Galaxy Watch3 SM-R855U
The firmware details for the Samsung Galaxy Watch3 SM-R855U include the Tizen-based wearable OS 5.5, an Exynos 9110 processor, and standard Odin flash files. Below is a brief breakdown of the official software specifications:
| Firmware Information | Details |
|---|---|
| Device Model | Samsung Galaxy Watch3 SM-R855U |
| Firmware Version | N/A |
| File Size | N/A |
| Android Version | Tizen-based wearable OS 5.5 |
| Platform | Exynos 9110 (10 nm) Dual-core 1.15 GHz Cortex-A53 |
| Release Date | Released 2020, August 06 |
| Region | Global, Africa and Asia |
| File Type | .tar.md5 / ZIP (Contains AP, BL, CP, CSC files for Odin) |
Which Firmware Version Should I Download?
You should download the firmware version that matches your current binary level and region code, with the latest version generally recommended for most users. Readers ask this question frequently, so I created a straightforward reference chart. Locate your specific scenario below to find the correct file:
| Your Situation | What I Recommend |
|---|---|
| Phone is completely dead or stuck on logo | the latest version, download this one. It is the latest Samsung Galaxy Watch3 SM-R855U firmware available. |
| FRP / Google account lock only | See the FRP bypass guide above, you likely do not need the full firmware for this. |
| Not sure which region/CSC to download | Check Settings › About Phone › Software Information for your current CSC, or enter Download Mode (Volume Down + Power), it shows the CSC on screen. Match the 3-letter code (e.g. XAA, BTU, INS) to the firmware filename. |
| Phone slow after a recent OTA update | Try the next older version, sometimes the latest OTA introduces new bugs and an older build runs better. Make sure the binary level is the same or higher than what your device currently has. |
| IMEI missing after a previous flash | Re-flash the latest version first, then follow the IMEI repair guide. Do not skip the reflash. |
| the latest version failed with a flash error | Try the next older version instead and double-check your AP/BL/CP/CSC file assignments in Odin before assuming the firmware is the problem. |
| Restoring to factory / warranty repair | the latest version, clean state, fresh start. |
To tell which Samsung firmware is newer, look at the last 4 characters of the PDA version string (e.g. S938BXXU9CZDP). The first character is the year (A=2024, B=2025, C=2026), the second is the month (A=Jan, B=Feb… L=Dec, Z=final stable), and the last two are the revision (0-9 then A-Z, where Z is highest). But before comparing dates, always check the binary level: the digit just before the date code (e.g. XXU9CZDP = Binary 9). You cannot downgrade to a lower binary level. If your device is on Binary 9, only flash Binary 9 or higher. Also make sure the 3-letter CSC code in the firmware matches your device region.
Download Samsung Galaxy Watch3 SM-R855U Firmware
You can download the official Samsung Galaxy Watch3 SM-R855U firmware directly from the links provided in this section. The most recent release available is the latest version. Once the download finishes, check that the file size aligns with the specifications listed earlier. A mismatch in file size typically indicates a corrupted or incomplete download, and attempting to flash a broken file often creates additional system errors.
Ensure you only download software that fully matches your specific hardware model. See the firmware selection guide above if you are not sure.
- Your model number is a variant of SM-R855U with a different letter suffix. Check About Phone carefully, one letter difference can cause a failed or broken flash.
- Your chipset differs from Exynos 9110 (10 nm) Dual-core 1.15 GHz Cortex-A53. Confirm in recovery mode before proceeding.
- You downloaded the file from a source other than this page.
- The file size differs significantly from the sizes listed in the table above, a size mismatch usually means a partial download, which will fail mid-flash.
Prerequisites for Samsung Galaxy Watch3 SM-R855U Firmware
Before installing the Samsung Galaxy Watch3 SM-R855U firmware, you must back up your data, remove all accounts, charge the battery, and install the proper USB drivers. Review this checklist prior to launching Odin for the Samsung Galaxy Watch3 SM-R855U firmware installation. Two common pitfalls affect Samsung hardware: forgetting to sign out of your Samsung account (which activates KG lock) and using a low-quality USB cable that drops the connection halfway through the process. Always rely on a high-quality data cable rather than a basic charge-only cord.
- Back Up IMEI Numbers: Dial *#06# and write down both IMEI numbers now. You will need these if you need to restore your IMEI after flashing.
- Remove Google Accounts: Sign out of all Google accounts to prevent FRP lock after flashing.
- Remove Samsung Accounts: Sign out of all Samsung accounts to avoid KG lock.
- Back Up Your Data: Back up everything, photos, contacts, WhatsApp chats, important files. Flashing wipes the device completely.
- Charge Your Device: At least 50% battery. A device that powers off during a flash is very difficult to recover.
- USB Cable & PC: Use a proper data USB cable, not a charge-only cable, and a Windows computer with available USB ports.
- Install Required Drivers:
How to Install Firmware on Samsung Galaxy Watch3 SM-R855U
You can install the Samsung Galaxy Watch3 SM-R855U firmware by loading the AP, BL, CP, and CSC files into Odin and clicking start while the device is in Download Mode. This guide utilizes Odin for the installation. Leave the “Auto Reboot” and “F. Reset Time” boxes checked inside Odin to ensure the cleanest possible outcome. If you feel unsure about which Odin build to operate, visit our Odin versions page. Certain older Samsung watches respond much better to previous Odin releases.
- Download and Extract:
- Download the correct firmware package from the links above.
- Extract the ZIP to a simple folder path, avoid paths with spaces or special characters, as some flash tools have trouble with them.
- Install the Listed Drivers:
- Confirm all drivers listed above are installed and that your PC has been restarted since installation. Skipping the restart is a common reason drivers do not work correctly.
- Load the Firmware File:
- In Odin, click “BL” and select the BL_*.tar.md5 file. Click “AP” and select the AP_*.tar.md5 file. Repeat for “CP” and “CSC”. Use HOME_CSC to keep data, or CSC for a clean flash.
- Connect Your Device:
- Enter Download Mode: Turn off your phone, then hold Volume Down + Power (add Home button on older models) until the warning screen appears. Press Volume Up to confirm and enter Download Mode.
- Connect your phone to your PC via USB. Odin should show “Added..” in the log area, this means your device is detected.
- Start Flashing:
- Click the “Start” button to begin.
- Do not disconnect, move the cable, or touch the device until the process is fully complete. Disconnecting mid-flash is how devices get bricked.
- Wait and Reboot:
- Once flashing finishes successfully, disconnect the device.
- Power on your device. The first boot will take longer than usual, give it up to 8 minutes.
Video Guide for Flashing
What to Expect After Flashing Samsung Galaxy Watch3 SM-R855U Firmware
After flashing the Samsung Galaxy Watch3 SM-R855U firmware, expect a longer initial boot time, warm device temperature, and a completely clean system state. Many users leave comments worried that the installation failed when everything is actually fine. Here is exactly what you should expect following a successful Samsung Galaxy Watch3 SM-R855U firmware flash:
- How to know the flash was successful: Odin will display a green “PASS.” message in the top-left corner of the log window. Seeing this indicates that the process completed properly.
- First boot takes 3 to 8 minutes, allow the device to sit without forcing a restart. The system is configuring itself for the first time. Interrupting this phase often causes bootloops.
- The phone will feel warm during first boot, this behavior is normal. The temperature will drop after a few minutes once the initial setup routines finish.
- All your apps are gone, this is standard. You will need to download them again from the Play Store. If you maintained a Google account backup, the setup wizard will give you the option to restore your applications automatically.
- Dial *#06# immediately after setup to verify your IMEI status. Complete this step before inserting a SIM card. If the screen displays “unknown” or “null”, refer to the IMEI repair guide below immediately.
- Be careful when re-adding your Google account, failing to remove it prior to the flash might trigger an FRP prompt. Enter your credentials fresh during the initial setup wizard rather than adding them later through the Settings menu.
- Wi-Fi, Bluetooth, and mobile data should function correctly right after the setup concludes. If mobile data fails to connect, navigate to Settings › SIM and Network and input your APN details manually, the flashing process occasionally wipes carrier APN configurations.
- Stuck in a bootloop after first boot? Access recovery mode and execute a factory reset from there, see the hard reset guide above. This happens occasionally and does not point to a firmware error, it usually stems from a conflict with leftover data from the previous installation.
- Samsung Smart Switch: Once you finish flashing your Samsung Galaxy Watch3 SM-R855U firmware, Samsung Smart Switch might suggest installing supplementary updates. Allow it to finish, this guarantees your hardware receives the most recent security patches designated for your area.
Missing IMEI or Corrupt Baseband on Samsung Galaxy Watch3 SM-R855U After Flashing?
A missing IMEI or corrupt baseband after flashing the Samsung Galaxy Watch3 SM-R855U usually means the EFS partition was wiped or corrupted during the process. When an IMEI disappears from a Samsung device following a flash, the EFS partition is typically to blame. This specific partition houses your IMEI details and network configurations. Keep in mind that writing a fake IMEI is illegal in many regions, so only attempt this if you are restoring the original number that came with the watch. Software like ChimeraTool or BFT can assist with the repair. Verify your local regulations before moving forward.
Video Guide: How to repair IMEI
Common Issues When Flashing Samsung Galaxy Watch3 SM-R855U
- Odin Shows “FAIL” Instead of “PASS”:
- This error typically occurs when the software region or model does not align with your hardware. Double-check your precise model number in Settings › About Phone before choosing your files. A single letter variation in the model code is enough to cause a failure.
- Samsung Galaxy Watch3 SM-R855U Not Recognized by Odin:
- Install the Samsung USB drivers again. Verify that the watch is actually in Download Mode. Test a different USB cable, Odin connections often fail with low-quality cords.
- KG Lock / Knox Triggered After Flashing:
- This security measure activates if a Samsung account remained logged in prior to the flash, or if unofficial software was applied. Always log out of Samsung accounts before beginning. Once KG lock is active, resolving it generally requires a professional unlocking utility.
- Boot Loop After Flashing:
- Open recovery mode (Volume Up + Power) and run a factory reset. This clears out residual data from the older system that might be creating a conflict.
Frequently Asked Questions
This FAQ section answers the most common questions about installing the Samsung Galaxy Watch3 SM-R855U firmware.
Q1: Will flashing the Samsung Galaxy Watch3 SM-R855U firmware erase my data?
A: Yes, installing this firmware via Odin resets the watch to its factory defaults, including the base Tizen-based wearable OS 5.5 configuration. Every application, photo, contact, and user account will be deleted. Save anything important before you begin the process. Data recovery is impossible once the installation finishes.
Q2: Is this firmware compatible with other Samsung models?
A: No. This specific software is designed exclusively for the Samsung Galaxy Watch3 SM-R855U operating on the Exynos 9110 (10 nm) Dual-core 1.15 GHz Cortex-A53 processor. Even a Galaxy Watch3 carrying a different letter suffix (for example, another SM-R855U variant) might rely on entirely different internal hardware. Loading the wrong software can leave the watch in a severe error state. Always verify your precise model number in Settings › About Phone.
Q3: Can I downgrade from the latest version to an older firmware version?
A: While technically possible on certain Exynos platforms, I advise against it. Moving backward can introduce security vulnerabilities and application instability on Tizen-based wearable OS 5.5. If the newest release is giving you trouble, leave a comment below, there is typically a safer solution than rolling back.
Q4: What should I do if I encounter an FRP lock after flashing?
A: Utilize our free Android apps launcher. The FRP lock on the Samsung Galaxy Watch3 SM-R855U engages whenever a Google account remains signed in prior to the flash. This is exactly why logging out of your Google account beforehand is highly recommended, it prevents the lock from appearing altogether.
Q5: Are custom ROM options available for the Samsung Galaxy Watch3 SM-R855U?
A: This tutorial focuses entirely on official Samsung stock firmware. The availability of custom ROMs for the Samsung Galaxy Watch3 SM-R855U depends on whether the Exynos 9110 (10 nm) Dual-core 1.15 GHz Cortex-A53 processor has open-source kernel support. Visit our Custom ROMs page or the XDA Developers forum to find custom software threads specific to this hardware.
Q6: My Samsung Galaxy Watch3 SM-R855U is not detected by Odin. What should I do?
A: Start by addressing the drivers, reinstall the Samsung USB drivers, reboot your computer, and attempt the connection again. Move to a USB 2.0 port if you are currently using USB 3.0, Samsung hardware tends to communicate more reliably over USB 2.0. Temporarily disable your antivirus software. If the problem continues, leave a comment below detailing the exact error message and I will assist you further.
Q7: How do I enter recovery mode on my Samsung Galaxy Watch3 SM-R855U?
A: Turn the watch off completely, then press and hold Volume Up + Power together until the recovery menu loads. On older Samsung hardware featuring a physical Home button, press Volume Up + Home + Power. The recovery screen will display the build number for your Samsung Galaxy Watch3 SM-R855U, which you can use to verify your current software version prior to a flash.
Q8: My IMEI shows “unknown” after flashing the Samsung Galaxy Watch3 SM-R855U. Is my phone permanently damaged?
A: No, the situation looks serious, but it is repairable. Follow the IMEI repair guide located in the troubleshooting section above. For Samsung hardware, inspect the EFS partition for corruption first. Crucially, do not insert a SIM card until the IMEI is successfully restored.
Q9: How long does it take to flash Samsung Galaxy Watch3 SM-R855U firmware?
A: The actual installation inside Odin generally requires 3 to 10 minutes, depending on the file size and your USB transfer speed. The initial boot following the installation takes additional time, usually between 3 and 8 minutes. Refrain from interrupting the watch during either phase. If the progress bar in Odin seems to pause, allow it a few extra minutes before assuming an error occurred.
Final Thoughts on Samsung Galaxy Watch3 SM-R855U Firmware
The Samsung Galaxy Watch3 SM-R855U firmware is the official and safest way to restore your watch to full working condition. You now have all the necessary resources to safely install the official Samsung Galaxy Watch3 SM-R855U firmware (the latest version) via Odin and restore your watch to normal operation. By carefully following the instructions, your hardware should now operate on a clean, stable software build.
If you run into an unexpected error or if a specific step does not work for your setup, please leave a comment below. Provide as much detail as possible, including the exact error message, your current step in the guide, and the troubleshooting steps you have already attempted. I review every comment and will help you resolve the issue.
If you found this tutorial helpful, please consider sharing it with others who might be experiencing similar software issues.
You can browse all Samsung firmware downloads for additional hardware models.
Disclaimer: Installing stock firmware is done at your own risk. Adhere strictly to the instructions provided on this page. I cannot accept liability for any damage to your hardware, but I will always do my best to assist you if an error occurs.
