Introduction: Why firmware and OS updates matter
Updating your smartphone’s operating system can feel exciting — new features, better performance, and improved security. But for users with locked or recently unlocked devices, firmware and OS updates can sometimes cause serious unlocking issues.
If you’ve ever installed an update only to find your phone “relocked,” your eSIM deactivated, or your network access restricted again, you’re not alone.
Software updates — whether it’s Apple’s latest iOS 18 or Samsung’s One UI 7.1 — can modify how the device communicates with carriers, how network locks are stored, or even reintroduce restrictions unintentionally.
This article explains how firmware and OS updates affect unlocking, what users should do before updating, and how professional unlocking services can help keep your device secure and permanently unlocked.
iOS Updates: What’s Changing and Why It Matters
Apple’s iOS updates often deliver new functionality — but they also tighten carrier control mechanisms, especially for devices that were carrier-locked at purchase.
1. iOS and Network Configuration Files
Every iOS update refreshes carrier settings — the configuration files that control how your iPhone connects to a network. If your device was previously unlocked unofficially or via incomplete carrier updates, these new configuration files can sometimes:
- Re-enable SIM restrictions if the unlock wasn’t processed at the IMEI database level.
- Remove custom unlock profiles added via temporary or software methods.
- Disable eSIM activation, showing messages like “eSIM cannot be activated” after update.
Tip: Always ensure your iPhone is unlocked through official IMEI-based methods before updating iOS. That way, Apple’s system recognizes your phone as permanently unlocked in their database.
2. Activation Lock and Carrier Re-Sync
When you install a major update — for example, iOS 17 → iOS 18 — your phone re-verifies activation data with Apple’s and your carrier’s servers.
If your carrier has not correctly updated your IMEI status (or if your phone was unlocked via temporary third-party software), the device may be flagged as still locked. This triggers messages like:
- “SIM not supported”
- “Unable to activate network”
- “Carrier policy update required”
In such cases, even previously functional SIMs can stop working until the unlock is revalidated at the database level.
Real-world example: Users who unlocked older iPhones via non-IMEI methods (e.g., “RSIM” or “Turbo SIM” bypasses) often found their phones re-locked after updating to iOS 17 or 18.
3. iOS 18 and eSIM Enhancements
Apple continues pushing eSIM adoption, especially in newer iPhones where physical SIM trays are removed entirely.
However, with that progress comes stricter carrier policies and regional lock variations. If your eSIM carrier profile was tied to a locked device, an iOS update could remove or disable that eSIM until the carrier re-approves it.
Pro tip: Unlocking your iPhone via IMEI before installing new iOS updates ensures smooth eSIM reactivation across regions and carriers.
Android & One UI Updates: The Firmware Factor
Android’s open ecosystem means more device variety — but also more variability in how updates affect unlocking.
1. One UI, OxygenOS, MIUI, and Beyond
Each Android brand builds its own firmware version over Google’s base OS. Samsung’s One UI, Xiaomi’s MIUI, and OnePlus’s OxygenOS all manage carrier locks differently.
Firmware updates on these platforms can sometimes:
- Reflash the baseband (the modem firmware controlling network access).
- Overwrite unlock configurations, reverting devices to locked status.
- Trigger Knox protection warnings (especially on Samsung), restricting network unlock capabilities.
Example: After upgrading from One UI 6.1 to 7.0, some users reported their previously unlocked devices showing “SIM network unlock PIN required” — even though the phone had been working fine before.
2. Region-Specific Firmware and Band Locks
Android updates can also install region-specific firmware that changes the supported frequency bands or carrier compatibility.
For example:
- A phone purchased in the U.S. may lose partial functionality on European bands after flashing new firmware meant for the North American region.
- Carrier-branded phones may automatically download updates optimized for that carrier — re-introducing network restrictions tied to that region.
Tip: Always check your phone’s CSC (Country Specific Code) before updating firmware. Unlocking through IMEI ensures your phone remains free to use global network profiles after any update.
3. Google’s Android 15: New Security Layers
Android 15 (expected in 2025/2026) introduces enhanced network integrity checks and deeper integration between firmware and carrier validation systems. While these updates improve security, they also increase the risk that phones unlocked via software patches or unauthorized tools will relock after the update.
A permanent IMEI unlock, however, remains unaffected — because it’s tied directly to the manufacturer and carrier database, not firmware versions.
What to Do Before Updating Your Phone
Firmware and OS updates can’t be avoided — but preparation can prevent headaches. Here’s what you should do before hitting “Install Now.”
1. Check Your Unlock Status
- iPhone: Go to Settings → General → About → Carrier Lock. If it says No SIM restrictions, you’re safe.
- Android: Insert a SIM from another carrier. If you get “Network locked” or “SIM not supported,” your phone is still locked.
2. Confirm Unlock Type
Ask your service provider or unlocking company how your device was unlocked. If it wasn’t done via official IMEI unlocking, consider re-unlocking before updating.
3. Back Up Your eSIM or Profile Data
For eSIM-only devices, back up your current eSIM plan details or QR code (if possible). Updates can sometimes delete or reset network configurations.
4. Delay Updates Temporarily
If you rely heavily on your phone for travel or business, wait a few days after a major update’s release. Early bugs often affect network and carrier compatibility, and manufacturers typically patch them within a week.
5. Use Wi-Fi for Updates, Not Mobile Data
Updating over Wi-Fi ensures your carrier network connection isn’t disrupted mid-installation — a small precaution that can prevent activation issues.
When to Seek Professional Help
Even with preparation, OS and firmware updates can still introduce unlocking issues that require expert attention.
You should contact a professional unlocking service if:
- Your phone relocks after a system update.
- You see “SIM not supported” or “Network unlock PIN” errors post-update.
- eSIM profiles disappear or fail to activate.
- You purchased a second-hand phone that suddenly lost network access after updating.
Professional services use database-level IMEI unlocks, ensuring that the unlock status is recognized globally — across firmware versions, updates, and regions.
Unlike temporary software unlocks, these official IMEI-based unlocks:
- Survive firmware and OS updates.
- Work with both physical SIMs and eSIMs.
- Maintain full manufacturer warranty and security integrity.
Pro tip: If your device is already unlocked, a professional verification service can confirm your IMEI’s unlock status before you update — minimizing risk.
Conclusion: Unlock Before You Update
Firmware and OS updates are designed to improve your phone — but for locked or recently unlocked devices, they can create unexpected obstacles. From carrier re-verification to new firmware restrictions, a simple update can disrupt your access if your device isn’t fully and permanently unlocked.
The safest approach? Unlock before you update.
Our professional IMEI-based unlocking service guarantees permanent, firmware-resistant unlocks for both Android and iPhone devices. Whether you’re running the latest One UI or iOS, our method ensures your phone remains network-free for life — through every update and across every carrier.
Avoid lock-in surprises. Unlock your phone today and stay update-ready for the future.