iPhone 17 Pro Max iPhone 17 (Pro / Pro Max) – FIXED! - Cellular modem fails to recover after signal loss

[kawa636r]

Final update (looks resolved in iOS 26.3 dev beta)



Apple released iOS 26.3 for developers today and I installed it immediately to test.



Key changes observed:

• Modem firmware downgraded from 1.20.06 → 1.20.03
• Carrier bundle updated for Movistar and Orange to 67.5.1

With this combination, I have not been able to reproduce the modem lock / “No Service but reachable” issue that was consistently reproducible before (loss of signal after Wi-Fi / coverage transitions, calls ringing for caller but never reaching the device).



After ~1h+ of testing in the same locations and conditions, the modem now recovers signal correctly every time.



This strongly suggests the root cause was carrier bundle + modem firmware interaction, not hardware.



Thanks to everyone who contributed — and hopefully this helps others who were seeing similar behavior.

 

[robrobrobro]

A lot of what you posted is over my head, but I've had some strange connectivity/wifi issues on my Air. I occasionally notice RCS messages not sending or receiving, or there's a delay. Wifi also seems to have problems- the range doesn't seem as good as my 13 Pro was in my house, and sometimes wifi doesn't seem to work at all even when in range and the icon says it's connected. Could these coming updates help that?

 

[kawa636r]

Update: iOS 26.3 did not fully fix the issue.

The modem lock / missed incoming calls still occurred, just less frequently.

After further investigation, I found a reliable workaround:

• Go to Settings → Cellular → Network Selection
• Disable Automatic
• Manually select your carrier (Movistar / Orange)

Since doing this, the issue has not reappeared across:

• iPhone 17 Pro Max (mine)
• iPhone 17 Pro (my wife)
• Another iPhone 17 from a coworker
  (both physical SIM and eSIM, Movistar & Orange)

Signal behavior is dramatically better (2G fallback now works, fewer drops, no modem freeze, hotspot stable).
This strongly points to a network selection / baseband roaming logic issue in Spain, not hardware.
Worth trying if you’re affected.

 

[Tsepz]

Update: iOS 26.3 did not fully fix the issue.

The modem lock / missed incoming calls still occurred, just less frequently.

After further investigation, I found a reliable workaround:

• Go to Settings → Cellular → Network Selection
• Disable Automatic
• Manually select your carrier (Movistar / Orange)

Since doing this, the issue has not reappeared across:

• iPhone 17 Pro Max (mine)
• iPhone 17 Pro (my wife)
• Another iPhone 17 from a coworker
  (both physical SIM and eSIM, Movistar & Orange)

Signal behavior is dramatically better (2G fallback now works, fewer drops, no modem freeze, hotspot stable).
This strongly points to a network selection / baseband roaming logic issue in Spain, not hardware.
Worth trying if you’re affected.

Thanks a lot, giving this a try, I actually remember this worked well on my older Symbian and Android phones too at my old place that had week signal.