Unable to update iOS 26.6.1 using cellular data

I had this issue: my MacBook, iPhone and iPad all running 26.6 refused to update to 26.6.1

Thanks to other people in this forum, the solution is to turn off "low data mode" under wifi / cellular settings and then remove the update via device storage then reboot. That fixes it.

What are you updating from? If it is from 26.6, it will be a smallish delta update probably weighting around 400-500 MB, but anything prior and you're looking at a huge full installer weighting over 8 GB (just checked) and that is heavy under any circumstances, Wi-Fi included. Plus you would have to have near unlimited data cap to be able to load that off the cellular network.

Then, there's the challenge of moving all that across with absolutely no errors till it is thru. As WheelieNick has said, better look for suitable Wi-Fi alternatives.

One more thing: the thing has to download, verify and unpack before installing. Make sure you have at least 3-4 times the expected installer size free on the phone before commencing.

@lobsterghost: I spoke to my carrier – and they do not restrict anything. The carrier never knows if you make an update – he only moves data. It is 100% the iPhone itself that makes the restriction to update iOS only over WiFi and not directly over mobile data. Btw: as said before: I connected my iPhone to the PC (tethering) and used the mobile data from the iPhone as internet source for the PC, and opened wifi hotspot. My iPhone then used mobile data to do internet access to serve the PC and the PC was WiFi-Hotspot for the iPhone. Meaning: the update was downloaded over mobile data of the iPhone – but not directly inside the iPhone, but over the PC and WiFi back to the iPhone. In that case any carrier restriction is excluded.

Yes, not being connected to Wi-Fi is likely the cause. iPhones often block large iOS system downloads over cellular data unless you explicitly enable high-data options, and unstable mobile signals frequently cause the update prep to freeze, spin indefinitely, or fail. 

unless you’re on a high data 5G plan, I recommend against updating over cellular networks

Hello Saegzz,

I also couldn‘t download the iOS 26.6.1 update by cellular on my iPhone.

Then I found a post saying that iOS 26.6.1 broke the cellular. So it came me the idea to use my other smartphone as a Wi-Fi hotspot and the update worked.

Let‘s hope that it‘s only iOS 26.6.

Sincerely

@Lawrence Finch: delivering the update from the apple server to the iPhone has two points to intervene: a) server is not allowed to send, or b) target is not allowed to receive.

In case a) it is apple that does not allow it; in case b) it is the device itself (the iPhone) that does not allow to receive it over mobile data directly, and is forced by apple to receive it over WiFi. So as it is the device it is also apple that does not allow it.

The carrier only transports the data – and in both cases it is the iPhone that is requesting the data and sending a send-update-command to the apple server. In case of mobile data it is the iPhone that communicates directly with the apple server; in case of Wifi it is also the iPhone that communicates with the apple server – but the signal does not go directly to the apple server but passes first over WiFi to the PC and through USB-cable back to the iPhone and then over mobile data to the apple server.

The carrier does not know or see what (kind of) data he is transporting. He just makes the connection between the two devices (in both cases the apple server and the iPhone) and transports the data from source to target. Arrived in the iPhone it is either directly used by the iPhone (what apple does not allow) or it is transferred to the PC over USB by the iPhone and then sent over WiFi by the PC. For the carrier the iPhone has always the same IP (by connecting to mobile data) with and without WiFi behind. What happens behind (through USB or WiFi) is not in competence of the carrier and he does not know about it.

Again: it is apple that does not allo the server to deliver the update or the iPhone that does not allow to receive the update when the iPhone asks for it connecting directly over mobile data. It is the device – the iPhone – that has the restriction to not allow iOS updates over mobile data directly and only allows to update when the update comes to the iPhone over WiFi. The carrier is not involved in that restriction apple has imposed – otherwise the carrier would not allow to transfer the update from the update server to the device even over USB and WiFi. Also with "tunneling" it is the iPhone (itself) that asks for the update at the apple server – not the PC.

@IdrisSeabright: the question is not who is right and who is not. The question is: why is it not possible to update the iPhone over mobile data directly but it is possible over WiFi – even when that same iPhone is receiving the mobile data and the internet access passes over the same mobile data of the iPhone?

It is apple that only allows iOS-update if the iPhone is connected to the internet over WiFi and not if the iPhone is connected to the internet over it's own mobile data connection.

The carrier is not involved (and not blocking it) – otherwise both ways would either work or both would not work.

Hello Saegzz,

I understand you are experiencing issues updating your iPhone to the latest version. I believe that there are 2 options to fix this

1) Use Wi-Fi. This can be at Home, Work, or your favorite coffee shop.

2) As other users have stated, turning off low power mode will help.

Thank you for using the Apple Support Community, and I hope this helps!

-Robert

I have this exact issue with update 26.6.1 & 26.6.2 and after speaking to Apple Store today they told me they have changed there policies and updates via mobile data is no longer supported they told me to go to the library or maccas or to get nbn internet. I have been doing software updates via mobile data for more than 10 years, so I’m pretty annoyed and this has convinced me to stop buying apple products.

@MD-R: german publication heise.de states that apple would fix the bug that update is not possible over mobile data with 26.6.2 ... (article in german / english language). So there does not seem to be a change in update policy that can be kept. Maybe apple tried; but too many users did not accept—and it does not make sense as many people only have one single internet access over mobile. Here it is almost standard that data amount is unlimited and speed is high (300 MBit/s or moer).

@EdsApples: it's obvious that updates from 26.6 to 26.6.1 and from 26.6.1 to 26.6.2 are not possible over cellular data; but with 26.6.2 the next updates (to 26.6.3 or 26.7 or 27) should again be possible over cellular data.

Scirob wrote:

Pre-iOS 26.6, this was not an issue for me so why now? Even connecting to my other iPhone’s personal hotspot doesn’t fix this. They want their users to suddenly use Wi-Fi, even if I have unlimited 5G plan (with my data consumption almost 100GB/day). Like saying their iPhones are incapable of updating itself via cellular (or another iPhone’s hotspot) despite the speed. Apple, it’s 2026 c’mon!

Sorry, but Apple hasn't stopped iPhone's updating over 5G and you're not speaking with Apple here anyway. This is a user to user only forum. What did your carrier say when you asked them about this? Your carrier is the one controls what you can do over cellular, not Apple.

Do you use T-Mobile? There have been many reports of update over cellular issues with T-Mobile. But that's a carrier issue, not an Apple issue.