If your Samsung phone suddenly became network locked after a recent update, this article explains why it happened and what you can do about it.
Since the January 2026 Samsung update, many users have reported that their phones, which were previously unlocked, became locked again after installing the update. This has been happening mostly on newer U.S. Samsung models, and in most cases the devices had been unlocked using what is commonly known as the Limited Country Unlock, also referred to as the Relock method.
After updating, affected phones may start showing messages such as Network Locked or Phone Locked. In some situations, the device may even ask for an MCK unlock code, including on carriers that normally do not require one. For many users, this comes as a surprise, especially if they were not aware of the unlock method originally used on their phone.
Why this happens after updates
The Limited Country / Relock unlock method works under specific conditions and relies heavily on software behavior. When Samsung pushes a major update or a security patch, those conditions can change. As a result, the system may silently reapply the original carrier lock during or after the update process.
This is why the issue suddenly appeared for many users after the January 2026 update.
How the relock can be fixed
In many cases, the relock can be fixed by flashing an older modem (CP) firmware, as long as it has the same BIT (binary) version as the firmware currently installed on the phone.
The BIT version is critical. Flashing a modem from a lower BIT version will not work, but using a compatible CP from the same BIT version can restore network access.
An important side effect of this method is that, because the modem version no longer matches the rest of the firmware, Samsung OTA system updates usually stop working automatically. This is actually useful in this situation, because it helps prevent the phone from updating again and re-locking itself.
In the video linked below, the entire process is shown step by step.
???? Video tutorial:
https://youtu.be/8B6Anm9Li2M
Preventing the relock from happening again
To be extra safe, it’s still recommended to manually disable Samsung system updates. In the video, I also show how to do this using ADB commands, which is the safest and most reliable method.
This update-blocking method is not only useful for this specific relock issue. It can also be used in general on Samsung phones if you want to avoid problematic updates, keep a stable firmware version, or prevent unexpected software changes.
The ADB commands used are:
To use ADB, you need Samsung USB drivers installed and Android Platform Tools on your PC. ADB is not included by default in Windows.
Samsung USB drivers can be downloaded from Samsung’s developer website, and Android Platform Tools are available directly from Google.
Affected and supported models
This issue has been tested or reported working on several newer Samsung models, including the Galaxy S25 series (SM-S938U, SM-S937U, SM-S936U, SM-S931U), the Galaxy S24 series (SM-S928U, SM-S926U, SM-S921U), as well as the Galaxy Fold 6 (SM-F956U) and Galaxy Flip 6 (SM-F741U).
The same fix may also work on other Samsung models, as long as an older modem with the same BIT version is available and the device was unlocked using the same method.
Tools used
The modem flashing process is done using Odin. The version used in the video can be downloaded here:
https://androidfilehost.com/?fid=9180008750105245345
Firmware files are sourced from SamFW.
Important note
Do not update the phone to a newer firmware with a higher BIT version. Once the BIT version increases, this fix may no longer be possible.
For phone repair and GSM service shops
If you run a phone repair or GSM service shop, situations like this can quickly turn into wasted time if you’re not prepared. For professional unlocking tools, firmware solutions, and GSM-related services, you can register at:
???? https://unlockresellers.com