Will an OS update remove my eSIM?
A normal OS update does not remove an installed eSIM profile, though settings such as which line carries data or whether roaming is on can revert to defaults. Check the cellular settings after updating, and if you update while travelling, do it on stable Wi-Fi.
After finishing an OS update, turning the phone back on and not seeing the line you were using, or sensing that some setting has shifted, is a worry many people run into after updating a device, especially anyone travelling at that moment who does not want to risk losing connectivity mid-trip. The short answer is that a normal OS update does not remove an installed eSIM profile, but there are a few settings that can revert to defaults, and it is worth checking every time after updating.
This page is written for anyone about to update the OS while travelling and wanting to prepare beforehand, anyone who just finished updating and now has a line that is not working, and anyone who wants to understand what an update can touch and what it cannot. We explain the real mechanism behind it, where problems most commonly appear, the steps to check afterward, and how to prepare before updating mid-trip.
What an OS update can and cannot touch
An eSIM profile installed on a phone is stored in a dedicated area separate from the part the operating system overwrites during an update. A normal OS update does not remove those profiles because it is a different piece of hardware from the part the update actually works on. This is a general principle that applies to most phones, though the fine detail can differ by brand, model, and the software version in force at that time.
What an update can touch is user-level software settings, such as which line is set as the default line for data, whether the data roaming switch is on or off, or the name given to each line. These are software settings that can sometimes reset back to system defaults during a major version update, unlike the eSIM profile itself, which is not removed.
Why some people feel the eSIM has disappeared after updating
The sense that an eSIM has disappeared usually comes from a line that was previously active being switched off automatically, or that line's data roaming switch being turned off back to default, leaving the internet unable to load even though the profile is still on the device normally. Another common case is the default line for data changing to a different line without you noticing, leaving the phone trying to use an unintended line instead.
Both cases are fixed by going back into the cellular menu after updating, not by reinstalling the profile from scratch, since the original profile is still on the device — only some setting reverted to default.
Steps to check after an OS update
- 1Open the cellular menu in settingsGo in and check whether the eSIM line you had installed still appears in the list — it should normally still be there.
- 2Check whether that line is switched on or offIf the line was switched off automatically, turn it back on yourself.
- 3Check that line's data roaming switchThis switch can revert to off separately from the line itself being on — turn it back on if you need cross-border data.
- 4Check the default data line is still set correctlyIf there are several lines, confirm the one set as default for data is still the eSIM you intend to use, not a different one the phone switched over on its own.
- 5Test by opening a web page or an app that needs the internetOpen a web page or app to confirm data actually works, rather than judging from full signal bars alone.
Updating while travelling: when to do it
If updating the OS while travelling, do it only on stable Wi-Fi, since an update typically uses a large amount of data and takes a while. Connecting over roaming data could burn through a large portion of your plan unnecessarily, or drop mid-update if the signal is not stable enough.
Choose an unhurried window, such as in the morning before leaving accommodation, rather than updating suddenly right before heading to the airport or during a layover. If something goes wrong mid-update, fixing it takes time and may again require stable Wi-Fi.
Summary table: what an update touches versus what it does not
| Part | Effect of a normal update |
|---|---|
| The installed eSIM profile itself | Not removed — remains on the device normally |
| Each line's on/off state | Can revert to default — worth checking again |
| The data roaming switch | Can revert to default — worth checking again |
| The default line for data setting | Can shift to a different line — worth checking again |
| A manually set APN value | Generally retained, but worth testing the internet again to confirm |
Common mistakes after an OS update
Checklist before and after updating during a trip
- Update only while on stable Wi-Fi
- Pick an unhurried window, not right before rushing to leave
- After updating, open the cellular menu and check every line's status
- Check the data roaming switch on the line you intend to use
- Check the default data line is still set correctly
- Test opening a real web page before leaving Wi-Fi
If everything checks out and the internet still does not work
If line status, the data roaming switch, and the default data line have all been checked and the internet still does not work, try toggling airplane mode once to force a full reconnection. If that still does not help, try restarting the phone again — sometimes an update needs an extra restart before the changed settings actually take effect.
If every step has been tried and it still does not work, message us with the device model, the OS version before and after updating, and the symptom seen. We can help check the plan's side and give further setting guidance, though we cannot fix the operating system's software directly, since that belongs to that device's own manufacturer.
An eSIM-related warning appears after updating
Sometimes after an OS update, the phone may show a warning related to a cellular line, such as prompting you to check settings again or briefly reporting no signal on one line. These messages are usually a side effect of the update process not yet finishing reconnecting to the network, not necessarily a sign the profile is damaged or gone. The exact wording differs by phone brand and software version, and we cannot explain the precise meaning of every possible warning, since the wording itself is set by that device's own manufacturer.
If a warning like this appears, wait a short moment for the phone to finish reconnecting to the network, then open the cellular menu and check the line's status again. If the message persists after trying a restart, that is the point to consider it may be a different issue worth checking further.
Differences between iPhone and Android after updating
Behaviour after updating can differ somewhat between iPhone and Android, since each brand designs its own cellular menu and eSIM profile handling differently. iPhone tends to keep most line settings fairly stable across an update, while some Android brands may add an extra verification or line-authorisation step after a major version update. The exact detail depends on the brand, model, and software version at that time, and we cannot give one universal answer that applies to every model.
Regardless of brand, the recommended check-after-updating steps on this page follow the same principle: open the cellular menu and check line status, the data roaming switch, and the default data line, all in full. If unsure what that model's menu calls each item, our device checker can serve as an initial reference.
Preparing before updating on a long trip
On a long trip where an OS update happens along the way, what can be prepared in advance is noting down which line is which, the name given to each, and settings such as the default data line, before tapping update — in case some of it needs resetting afterward. Having this note ready makes restoring the settings faster, without having to recall what was originally set from memory.
The phone restarts repeatedly after updating
If the phone restarts itself repeatedly after an OS update, or gets stuck on the logo screen unusually long, that is a problem with the software update process itself, not something related directly to the eSIM profile, even though the knock-on effect can be that the cellular menu is temporarily unreachable. In this case, resolving the update itself comes first — letting the phone finish updating without cutting power or unplugging midway — and then going back to check the cellular line once the phone is working normally again.
A problem like this sits with the phone's own operating system and hardware directly, outside anything we can adjust. If the phone stays stuck unusually long even after waiting and restarting, that device's own manufacturer or service centre is who to contact directly, and the cellular line can be checked with us again once the phone is working normally.
Keeping a screenshot of the unusual message before contacting that manufacturer usually helps describe the symptom more precisely than words alone, and if a question specific to our own plan comes up afterward, such as the expiry date or remaining data, that can still be raised with us separately as usual, whether the device-side issue is already resolved or still in progress.
常見問題
Will an OS update remove my eSIM?+
A normal update does not remove an installed eSIM profile, though some settings, such as the default data line or roaming switch, can revert to defaults.
The internet does not work after updating — what should I check first?+
Open the cellular menu and check the line is still on, data roaming is on, and the default data line is set correctly, before assuming the profile is gone.
Should I update the OS while travelling?+
Only do it on stable Wi-Fi, and choose an unhurried window, to cut the risk around data volume and problems mid-update.
Can I remove the profile and reinstall using the same QR code?+
Usually not, since most QR codes or installation files only work once. Always check the settings first, and do not remove a profile until you are sure.
Why does the default data line change on its own after updating?+
Some OS versions reset user-level settings back to defaults during a major update — this is the operating system's own behaviour, not the eSIM profile's.
Everything has been checked and the internet still does not work — what next?+
Try toggling airplane mode and restarting the phone again. If that still does not help, message us with the device model and the OS versions before and after updating.
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