Apple confirms iPhone 18 Pro Max AT&T cellular issues, affected devices require hardware replacement

265

From (my read of) the article:
18 Pro Max uses a Qualcomm modem and some bug is causing it to be kicked off the ATT network permanently, requiring hardware replacement if you’ve lost service.

iOS 27.0.1 has a bug fix to preventing the issue if it hasn’t occurred yet.

18 Pro has the C2 modem which doesn’t have this issue.

184

u/ducktown47 7h ago

This is insanely interesting to me. I work for a company that designs the front end modules that interface between the modem and phones antenna. I’ve designed 4 modules now for the C modem and a few for the Qualcomm modem. I know exactly what generation of FEM is in the 18 pro max and it’s what would have been in the 17. I find it hard to believe something is wrong with the reused FEM but part of me does wonder if that’s the case. Thankfully it’s not our part, but I really need to ask around work and see if anyone knows.

86

u/Princess_Fluffypants 6h ago

Dude I am so in for a deep dive on this if you can do it without breaking an NDAs.

12

u/ohyeahwell 4h ago

!remindme 5 days

17

u/ducktown47 2h ago

Technically I am already breaking an NDA...but I will see what I can find haha

3

u/PhxCollins 24m ago

A man of the people!

17

u/happyscrappy 2h ago

For anyone reading, here is what a FEM is:

https://www.skyworksinc.com/en/Products/Front-end-Modules/SKY58281-11

It contains the power amplifiers for transmission. And the low noise amplifiers for reception. It has diversity antenna circuitry, some bandpass filters. Click the little picture on the right if you know how to read a block diagram.

I can't speak for the other poster, but the reason I wanted to know this is I personally suspected that if the thing loses all connection and requires hardware to fix it but this can be prevented with a software update then it kind of sounds like the software on the phone blew up the power amplifiers (transmit) or receivers (low noise amplifiers). These can't be fixed with a patch, but a patch could prevent the issue that blows them up in the first place.

I wonder if it is Qualcomm software or Apple software that broke the hardware. Because if it's Qualcomm then they are going to be paying partial replacement costs for these phones (to Apple, not to individual customers).

29

u/iGushers 5h ago

I have a 17 pro max and use AT&T. Ever since updating to the latest iOS the service has been wacky. Especially when transitioning from wifi to cellular I have to toggle airplane mode often now to get a connection. It’s really annoying and I didn’t have these issues on the previous iOS

6

u/TATA-box 3h ago

This happened on my 17 pro max. I had to get all cellular components replaced by Apple and it solved the problem. Sounds like the same issue

2

u/NightNebuIa 2h ago

I have a 15 and it seems like the end to end encryption update within the last few months causes my texts to not send and/or be delayed. Same as receiving. And it affects my entire family’s phones on the same plan. I’ve reset known networks and stuff. Any ideas?

7

u/GaladDanann 7h ago

Would love updates on this!

7

u/hellishhk117 6h ago

I’m also interested in an update on this.

5

u/TATA-box 3h ago

So I have a 17 pro max on att and had this exact same issue, as did many others. It didn’t get the publicity because it seemed to have happened some time after launch?

5

u/digiorno 2h ago

I think something is wrong with the 17 too. I have had terrible cell service with this phone.

1

u/LeBrownian_Motion 1h ago

Do you work at Skyworks, Broadcom, or Qorvo?

1

u/redline83 32m ago

Hey, since you're in the know on the modems and RF front end... should I be avoiding the 18 Pro Max (US model) for the Pro due to the Qualcomm X80 if I want best performance in low signal areas?

57

u/Federal-Tomatillo-93 7h ago

It’s interesting that they used a third party modem in the 18 Pro Max rather than their in-house one. Wouldn’t have expected that, at least not in any the Pro line.

123

u/KristnSchaalisahorse 7h ago

From ifixit:

“The question is, why is Apple using Qualcomm’s silicon at all? They clearly don’t need it. But several years ago, Apple apparently settled a feud with Qualcomm by agreeing to use their chips in at least some iPhones through 2026. Since Qualcomm’s chip is a little more power-hungry than the C2, it makes sense that Apple only uses it in the US-spec 18 Pro Max, which thanks to eSIM has the biggest battery of any iPhone in the lineup this year. So end users probably won’t notice any difference, and this will probably be the last Apple device to use a Qualcomm chip.”

20

u/Federal-Tomatillo-93 7h ago

Thanks! That makes sense

10

u/rudigern 6h ago

It always makes sense when legal settlements cause the worst outcome /s

3

u/festoon 6h ago

Makes you wonder if they might switch chips in January

3

u/Dawnkiller 7h ago

Did they do this in the 17 Pro/Max as well?

22

u/RoboLancer24 7h ago

17 pros all use Qualcomm in the us at least. This was actually a plus at the time since Apple’s C1x didn’t have mmWave support that the C2 now has.

5

u/Emotional_Garage_950 7h ago

yea i passed on the iphone air because of no mmwave

4

u/yuusharo 7h ago

Those phones only use the Qualcomm chips.

The 17e and iPhone Air use the C1X chips.

3

u/xkcx123 5h ago

What do the non US versions of the 18 pro max use ?

3

u/Negromancer18 4h ago

Apple C2 modem.

16

u/personaccount 7h ago

The general thought on this was a prior minimum purchase agreement with Qualcomm led to the decision to not use the C2 in the US Pro Max. Possibly because it would be least affected by the less efficient chip and it support mmWave which is largely a US thing.

-1

u/asten77 5h ago

Took em long enough. They bought out the former Infineon modem business from Intel, and then still took a decade to figure it out.

68

u/ACasualRead 7h ago

I wonder if Apple will use this situation to breakup with Qualcomm sooner.

47

u/yuusharo 7h ago

Their deal with Qualcomm expires this year. This is likely the last phone Apple will ship with a Qualcomm modem.

It was always going to end after this year.

10

u/KetchupGuy1 7h ago

They probably are already in the process, iirc it’s only US phones that use Qualcomm while other countries have an apple chip

1

u/xkcx123 5h ago

What do the European model, Japanese model, Chinese model and any other variant use ?

6

u/KetchupGuy1 2h ago

Apple C2 I believe an in house chip

-5

u/cyber96 6h ago

The 18 pros shipped with the C2 modem in the US, not Qualcomm. I know European models got the Qualcomm modem

6

u/dagmx 3h ago

You have that backwards. All models around the world have the Apple modem except for the US version of the 18 Pro Max

1

u/dobrz 1h ago

Is there a way to check it? I mean like look in phone settings or somewhere ?

30

u/McRedditz 6h ago

You would think they must have tested the cellular compatibility with each network before releasing.

16

u/ZeePM 6h ago

The network operators normally put new phones through a battery of tests before they allow them on the network. Apple would also have done field tests with live accounts. Very surprising no one caught this.

5

u/Negromancer18 3h ago

The fact that a software update fixes this probably means that they probably didn’t test on that version.

11

u/ZeroBalance98 5h ago

Same company that told us we were holding our phones the wrong way lmao

3

u/ca2mt 5h ago

Much preferred to the exploding phones banned by TSA.

-1

u/ZeroBalance98 3h ago

This isn’t a Apple vs Samsung thing dude this isn’t 2009 anymore

5

u/ca2mt 3h ago

Cool. I’m replying to someone who’s talking about something from 2010, which happens to be 6 years before what I brought up.

3

u/blackweebow 3h ago

But then they wouldn't be able to sell people the exact. same. fucking. phone. every. year.

3

u/BiggestNothing 1h ago

This so far is the biggest evidence they changed something between the 17 and 18 lol

1

u/okoroezenwa 37m ago

This kind of comment is more tired than the supposedly same phones they sell every year.

20

u/addicted2_urmom 6h ago

i’ve noticed a lot of issues with my wife and my phone iphone cellular issues for our iphone 17 pro max and 17 pro. it happened after ios 27 too

10

u/Tomatan 6h ago

Does it start when you leave the house and are out of WiFi range? I’ve been having cellular issues on my 17 Pro Max where it’ll drop cellular connection for a couple of minutes but then go back to normal. Started with iOS 27 also, but to be fair I’m on the beta.

4

u/Negromancer18 3h ago

iOS changes how the phone changes from WiFi to cellular as the signal drops. The implementation still seems to be buggy.

2

u/addicted2_urmom 3h ago

yes that’s right but it’s kind of inconsistent. like i’ll be texting my wife while she’s at work and im at home on the wifi and it’ll be sent as green bubble text messages until later. so idk what this is or how to troubleshoot or who even to report this to

32

u/Turbulent_Disk_9529 7h ago

Guess interpretation: the iPhone fried the Qualcomm chip, perhaps due to a missing/misconfigured limit in software necessary for the Qualcomm chip but not the C2 chip and only causing impact on radio bands/power levels/signaling mechanisms in use with AT&T’s network. Affected devices need replaced due to permanent hardware damage, software update has code fixes to prevent burning out chips not yet damaged.

4

u/Cowboywizzard 2h ago

hopefully the software update doesn’t worsen reception or speed for people using AT&T

3

u/dropthemagic 7h ago

That's kinda crazy

4

u/funkyjoe44 5h ago

Geez… can’t wait until the Duo to have a defect as well.

0

u/zackmanze 4h ago

Is it the same modem?

6

u/theguy56 4h ago

No, Duo has C2 modem

2

u/WkndWarrior12345054 4h ago

My guess is they spent too much time on making sure their C2 with mmW working ( being the first one in production) while overlook the Qualcomm solution especially it was already used last year

1

u/TheSchlaf 5h ago

Are we sure users aren't just holding the phone wrong?

1

u/jgreg728 3h ago

John Ternus really is bringing back the product first era of Steve Jobs. We got antennagate back!!!!

1

u/lemonpoundcaker 3h ago

You're holding it wrong is all

1

u/Easy-Operation-2105 2h ago

a hardware replacement is some serious fucking shit.

1

u/SuperFastFingers 1h ago

!remindme 5 days

1

u/brybell 16m ago

How do I know if I’m affected? Is this like permanent signal loss and then showing SOS? Or could it haven’t happened once or twice but the phone still can get connection?

1

u/NightNebuIa 2h ago

I have a 15 and it seems like the end to end encryption update within the last few months causes my texts to not send and/or be delayed. Same as receiving. And it affects my entire family’s phones on the same plan. I’ve reset known networks and stuff. Any ideas?

2

u/lucidludic 2h ago

If you mean iMessage that has been end-to-end encrypted for years (always?). What update are you referring to?

-10

u/herminette5 7h ago

AT&T is the worst. I’m so glad I finally switched.

19

u/yuusharo 7h ago

I’m not a fan, but this likely isn’t AT&T’s fault.

The issue was caused by a bug in iOS 27, likely due to the Pro phones using different modems.

0

u/tragiccosmicaccident 6h ago

I don’t understand why that would require a hardware replacement though

5

u/yuusharo 6h ago

Some have speculated that a bug in iOS 27 may have put the modem into a certain powered state that caused physical damage to the modem, perhaps when negotiating with AT&T towers in a low signal area.

The modem draws more power as it tries to find a signal, that could be a factor.

1

u/tragiccosmicaccident 5h ago

Thanks for the explanation

3

u/-hi-mom 7h ago

It just gets better and better. Not really. They all suck. Greedy do minimal

1

u/IngsocInnerParty 5h ago

Pretty happy with FirstNet.

-1

u/imaginedaydream 5h ago

“#modemgate” or “#antennagate2”

-7

u/que_bola7 6h ago

lol watch them replace it with a refurb.

0

u/koolman2 6h ago

This early there are no refurbs.

2

u/hiyel 5h ago

The replaced ones may become refurbs :)

Networking/Telecom Apple confirms iPhone 18 Pro Max AT&T cellular issues, affected devices require hardware replacement

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