Samsung Knox Warranty Check Guide
Samsung Knox is a unique security feature that permanently records if a phone has been modified. Learn how to check Knox warranty status and why it's critical when buying a used Samsung.
What is Samsung Knox?
Samsung Knox is a defense-grade security platform built into Samsung smartphones at the hardware level. It provides secure boot, real-time kernel protection, and trusted execution environments for sensitive operations like Samsung Pay, Secure Folder, and enterprise data protection.
One of the most important features of Knox is the warranty void fuse (eFuse). This is a one-time programmable hardware component that permanently records whether the device has been tampered with:
- Knox Warranty Void: 0x0 — The device has never been modified. Warranty is intact
- Knox Warranty Void: 0x1 — The device has been rooted or modified. Warranty is permanently voided
Once the eFuse is tripped (set to 0x1), it cannot be reset by any means—software or hardware. This is a permanent, irreversible change.
For more on Samsung security, see our Samsung blacklist check guide and Android IMEI check guide.
What Trips the Knox Fuse?
The following actions will trip the Knox fuse and permanently void your warranty:
- Rooting: Gaining root/administrator access to the Android system
- Custom firmware: Installing custom ROMs, kernels, or recovery images
- Bootloader unlocking: Unlocking the bootloader (on supported models)
- Flashing unauthorized software: Using Odin to flash non-official firmware
- Downgrading firmware: Installing an older version of the OS
- Modifying system partitions: Any tampering with system-level files
Once any of these actions is performed, the Knox eFuse is permanently tripped, and the following features are disabled:
- Samsung Pay
- Secure Folder
- Samsung Pass
- Enterprise Knox features (MDM, Knox Configure)
- Warranty service at Samsung service centers
How to Check Samsung Knox Warranty Status
Method 1: Phone INFO App (Recommended)
The most reliable way to check Knox warranty status on the device:
- Download Phone INFO or Samsung Phone INFO from Google Play Store
- Open the app and grant necessary permissions
- Look for Knox Warranty Void status
- If it shows 0x0, Knox is intact and warranty is valid
- If it shows 0x1, Knox has been tripped and warranty is voided
Method 2: Samsung Members App
- Open the Samsung Members app (pre-installed on Samsung phones)
- Go to Support
- Check device status and diagnostics
- Look for any warranty or security status warnings
Method 3: Service Mode (Some Models)
On some Samsung models, you can access service mode:
- Open the Phone app and dial
*#0*# - This opens the service menu (if supported)
- Look for device status or warranty information
Note: This code may not work on all models or carrier-locked devices.
Method 4: IMEICheck (Remote Check)
Use IMEICheck to check Samsung warranty status remotely:
- Get the IMEI (dial
*#06#) - Enter it on IMEICheck
- Review the Samsung warranty section of the report
Note: IMEICheck shows manufacturer warranty status. For Knox-specific tripped status, use the Phone INFO app on the device itself.
Method 5: Samsung Service Center
Take the phone to a Samsung authorized service center. They can check the Knox status and warranty using their internal diagnostic tools.
Samsung Warranty Coverage
| Component | Warranty Period |
|---|---|
| Phone (main device) | 12-24 months (varies by region) |
| Battery | 12 months |
| Charger | 12 months |
| Earphones | 6 months |
| Screen (manufacturing defect) | 12-24 months |
For warranty comparisons, see our Huawei warranty and Google Pixel warranty guides.
Why Knox Warranty Matters When Buying Used
When buying a used Samsung phone, Knox warranty status is one of the most important checks:
- Warranty validity: A tripped Knox means no warranty service—ever. Samsung will refuse repairs even for manufacturing defects
- Samsung Pay: A tripped Knox disables Samsung Pay permanently, which is a key feature for many users
- Security concerns: A tripped Knox indicates the phone was rooted or modified, which may introduce security vulnerabilities
- Resale value: Samsung phones with tripped Knox have significantly lower resale value
- Software stability: Rooted phones may have stability issues, custom ROMs, or malware
- Banking apps: Many banking and financial apps refuse to run on devices with tripped Knox
Buying a Used Samsung: Knox Checklist
- Check the IMEI: Dial
*#06#and run a check on IMEICheck - Check Knox warranty: Use Phone INFO app to verify Knox is not tripped (0x0)
- Check Samsung Pay: Try opening Samsung Pay—if it fails, Knox may be tripped
- Check Secure Folder: Try creating a Secure Folder—if it fails, Knox is tripped
- Check blacklist: Run a Samsung blacklist check
- Check carrier lock: Verify the phone is unlocked
- Check for root: Look for SuperSU, Magisk, or other root management apps
- Test all features: Camera, fingerprint, Samsung Pay, Bluetooth, WiFi
For more buying tips, see our IMEI check before buying guide and phone originality guide.
Common Issues When Checking Samsung IMEI
When checking your Samsung phone's IMEI, you may encounter these common issues:
Issue 1: IMEI Shows "Invalid" or "Unknown"
This can be caused by:
- Typos: The IMEI is a 15-digit number. Double-check every digit and avoid letters or spaces.
- Baseband firmware issues: After flashing or system updates, the baseband may be lost. Dial
*#06#to verify if the IMEI displays. - Motherboard repair history: If the phone has had motherboard repairs, the IMEI may have been erased or overwritten.
Issue 2: IMEI Shows "Blacklisted"
If your IMEI check shows the device is blacklisted, it means the phone may be reported lost, have unpaid bills, or be involved in fraud. Recommended actions:
- Contact the seller to confirm the phone's origin and status
- Check with the carrier for the specific blacklist reason
- If you purchased a used phone, request a refund immediately
- If your own phone was incorrectly reported, file an appeal with your carrier
Issue 3: Two Different IMEI Numbers
Dual-SIM phones have two IMEI numbers corresponding to SIM1 and SIM2 slots. The TAC code (first 8 digits) should be identical for both, with only the serial number (last 7 digits) differing. If the TAC codes differ, the motherboard may have been replaced or there may be hardware issues.
Real-World Samsung IMEI Verification Cases
Case 1: Refurbished Phone Detection
A user purchased a Samsung phone from a secondhand marketplace, with the seller claiming it was "brand new, unopened." An IMEICheck report revealed:
- Activation date was 8 months earlier than the seller's claimed purchase date
- Warranty status showed "expired"
- Device was flagged as "officially refurbished"
The user successfully obtained a refund using the IMEI report as evidence.
Case 2: Blacklist Evasion
A user bought a Samsung phone from an unauthorized channel. After 3 months, the phone suddenly lost network connectivity. An IMEI check revealed the device had been blacklisted by the carrier due to unpaid bills. Failure to check the IMEI before purchase resulted in financial loss.
Samsung Model-Specific IMEI Considerations
Different Samsung phone series have specific IMEI verification considerations:
| Model Series | IMEI Notes | Key Verification Points |
|---|---|---|
| Flagship Series | Full warranty and activation date queries available | Check that activation date matches purchase date |
| Mid-Range Series | Blacklist and model verification supported | Check regional version (frequency bands vary by region) |
| Entry-Level Series | Basic IMEI verification available | Watch for clone phones; check hardware info alongside IMEI |
Complete Samsung Used Phone Buying Checklist
Beyond IMEI checking, here's what to verify when buying a used Samsung phone:
- Physical inspection: Screen scratches, frame dents, camera dust, charging port wear
- Function testing: WiFi/Bluetooth/GPS connectivity, speakers/microphone, face unlock/fingerprint
- Battery health: Check maximum battery capacity in settings (recommended >85%)
- Screen test: Check for dead pixels and burn-in on full white/black backgrounds
- Account lock check: Ensure all accounts are signed out (Apple ID / Samsung Account / Xiaomi Account etc.)
- Carrier lock check: Test with SIM cards from different carriers
- IMEI consistency: IMEI from *#06# / Settings / Box should all match
⚠ Important Reminder
If a seller refuses to provide the IMEI for verification, this is a clear red flag. Legitimate sellers have no reason to prevent buyers from checking a device's status.
FAQ
What is Samsung Knox warranty void?
Samsung Knox warranty void is a status flag that indicates whether the Knox security hardware has been tripped. When you root a Samsung phone, install custom firmware, or make unauthorized modifications, the Knox fuse is permanently tripped (set to 0x1). This voids the warranty and disables Samsung Pay, Secure Folder, and other Knox features. The tripped status cannot be reset.
How do I check my Samsung Knox warranty status?
To check Samsung Knox warranty status: 1) Download and run Phone INFO app from Google Play, 2) Look for Knox Warranty Void status, 3) Or dial *#0*# for service mode (works on some models), 4) Or check in Settings > Biometrics and security > Knox. You can also use IMEICheck to check Samsung warranty status by IMEI.
Can Samsung Knox be reset?
No, Samsung Knox cannot be reset once tripped. The Knox warranty void flag is stored in a hardware fuse (eFuse) that is permanently burned when triggered. There is no software or hardware method to reset it. The only way to get a non-tripped Knox is to use a Samsung phone that has never been rooted or modified.
Does rooting Samsung void warranty?
Yes, rooting a Samsung phone voids the warranty permanently. When you root the device, the Knox fuse is tripped, which is detectable by Samsung service centers. Even if you unroot the phone later, the Knox tripped status remains. Samsung will refuse warranty service for any device with a tripped Knox.
What does the TAC code in IMEI results mean?
The TAC code (Type Allocation Code) is the first 8 digits of the IMEI, representing the device model and allocation. It precisely identifies the phone's model, manufacturing origin, and production batch. The GSMA database records all legitimate TAC-to-model mappings.
Can a blacklisted phone be unblacklisted?
Yes, but only under certain conditions: if blacklisted due to unpaid bills, paying the balance may allow removal; if reported lost and then found, you can apply for removal with proof of purchase and ID. However, phones blacklisted for fraud or theft typically cannot be unblacklisted. Contact your carrier for specific removal procedures.
How to identify a fake phone?
IMEI checking is one of the most reliable methods. Genuine phones have IMEI records in the GSMA database, and the queried model should match what's shown in phone settings. Clone phones often use copied IMEI numbers, which may show mismatched model information. Also verify that hardware specs (CPU, RAM, screen resolution) match official parameters.
How long does an IMEI check for Samsung take?
Basic IMEI checks (model identification, blacklist check) typically return results within seconds. Detailed reports (including warranty status, carrier lock, activation date) may take 30 seconds to several minutes, depending on data source response times. IMEICheck aggregates information from multiple databases.
Conclusion
Samsung Knox warranty status is a unique and critical check when buying a used Samsung phone. Unlike other brands where modifications can be hidden, Samsung's Knox eFuse provides a permanent, tamper-proof record of whether the device has been modified. Always check Knox status before buying a used Samsung—a tripped Knox means no warranty, no Samsung Pay, and no Secure Folder, significantly reducing the phone's value and functionality.
Check your Samsung warranty status at IMEICheck—enter your IMEI for comprehensive results.