New iOS 5.0.1 Build 9A406 Intended to Fix 'No SIM Card' Errors on iPhone 4S - MacRumors
Skip to Content

New iOS 5.0.1 Build 9A406 Intended to Fix 'No SIM Card' Errors on iPhone 4S

Yesterday, we noted that Apple had quietly released a tweaked version of iOS 5.0.1. The purpose of the tweak was a mystery given that the update was not being pushed to all users and only made available to those newly updating to iOS 5.0.1. The new version arrived as Build 9A406, and increment of one over the original iOS 5.0.1 release.

But based on a new Apple support document, it now appears that the updated build may have been designed to address an issue some users have been experiencing with SIM card-related errors. With the update affecting a relatively small portion of users, Apple may have elected not to push it out to all users in the form of an iOS 5.0.2 software update, and instead rely on those users who are having problems following Apple's advice and obtaining the new build through the restore process outlined as a solution for the issue.

no sim card installed
Last month, some attention was turned on Apple as a quickly-growing thread in Apple's discussion forums revealed a number of users experiencing problems with either a "No Service" or "No SIM Card Installed" warning popping up on their iPhone 4S devices. From Apple's new support document:

In certain situations, iPhone 4S may have difficulty recognizing a micro-SIM card, resulting in the following behaviors:

- "Invalid SIM" or "No SIM Card installed" alert appears intermittently.
- Status bar displays "No Service" or "Searching" in a location with good network coverage.

Apple goes on to describe the recommended solution for the issue, which involves backing up and then restoring the device, an action that involves iTunes pulling down the new Build 9A406 of iOS 5.0.1 and installing it on the user's device. Once the device's system has been restored, the user can then restore content and settings from a backup.

1. Back up your user content and settings using iTunes or iCloud. See this article for more information.
2. Restore your iPhone 4S using iTunes.
3. After the process is complete, restore your user content and settings from your backup.
4. To confirm that you've successfully restored, verify that the version is now iOS 5.0.1 (9A406) in Settings > General > About.

Unfortunately, user reports on the new build appear to be mixed, with some users reporting that it does indeed fix their "no SIM card" issues while others have seen no improvement. It is unclear at this time exactly why results are mixed and whether the fix addresses only some subset of the root causes of the issue or if some other factor is in play. Consequently, we may have to wait for more users to try applying the update before drawing more specific conclusions.

Related Forum: iPhone

Popular Stories

iCloud iPhone 17 Pro

iPhone Users Who Pay for iCloud Storage Get Two New Perks on iOS 27

Tuesday June 9, 2026 11:29 am PDT by
If you pay for extra iCloud storage on your iPhone, beyond the 5GB included for free, you might receive two more perks on iOS 27 at no additional cost. First, Apple said there will be daily usage limits for some of the new and enhanced Apple Intelligence features on iOS 27, including image generation. However, the company noted that "increased access" is available with "most" iCloud+ storage ...
CarPlay Siri AI

Apple Announces New CarPlay Features on iOS 27, Including Video Apps

Monday June 8, 2026 4:17 pm PDT by
Back at WWDC 2025, Apple revealed that it was planning to allow CarPlay users to watch video via AirPlay in their vehicles while they are not driving, but we did not hear many specific details about this functionality until now. In a WWDC 2026 video aimed at developers, Apple said the CarPlay video feature is available in new vehicles that support it. When playing a video in an iPhone app...
Apple Says iOS 27 Adds These 12 New Features to Your iPhone Feature

Apple Says iOS 27 Adds These 12 New Features to Your iPhone

Tuesday June 9, 2026 9:47 am PDT by
iOS 27's key new feature is a more intelligent and personal version of Siri, but the changes go well beyond that. In a press release today, Apple outlined additional enhancements coming across Apple Maps, Find My, Apple Wallet, Apple Music, and more. Apple Maps has gained an enhanced Flyover experience powered by AI, enabling you to view aerial imagery in "stunning detail" for select cities. ...

Top Rated Comments

189 months ago
Just give me 5.1 and please make my battery better.
Score: 6 Votes (Like | Disagree)
189 months ago
Now why wouldn't Apple release 5.0.1.1 or 5.0.2?
Score: 3 Votes (Like | Disagree)
PurrBall Avatar
189 months ago
If you're still having the problem, just go to your carrier and get a new SIM. Worked for me.
Score: 2 Votes (Like | Disagree)
Piggie Avatar
189 months ago
Jeez, how can one company have so many problems with just one phone.

Can you imagine the mess they'd be in if they had 20 or 30 phones they had to support!

Amazing.
Score: 2 Votes (Like | Disagree)
189 months ago
RE: Battery

I don't know about anyone else's experiences with this whole issue is but I had VERY POOR battery issues with the 1st iPhone 4S I purchased and no matter what nothing could/would fix it. Second iPhone 4S, better battery but still lacking on iOS 5.0 and 5.01. I am now finally seeing OUTSTANDING battery life on iOS 5.0.1 9A406. I had tried the developer releases (both of them) but neither helped with poor battery issues... I choose to roll back to iOS 5.0.1 9A405 until this new release came out, oddly it was about 50MB smaller than 9A405, I suspect it is missing the Carrier IQ stuff... Just a guess though

Of course, YMMV so take it for what it's worth but I am still on 100% battery with light usage (checked email and loaded Facebook) with about 4 hours standby included... Very pleased

:)
Score: 2 Votes (Like | Disagree)
garylapointe Avatar
189 months ago
Delta Updates?

I thought one feature of the new iOS was to be able to do minor incremental updates and not have to do major updates...

That should make something like this relatively minor. And it should have a new number if there are changes, you shouldn't have to know the version and the 4 digit hex code. 5.0.1b would work just fine....

Gary
Score: 1 Votes (Like | Disagree)