The tech giant Apple, Inc., quietly released a tweaked version of the iOS 5.0.1 that can fix a bug on the SIMs for iPhone 4S.

The original build number of iOS 5.0.1 was 9A405. However, the updated version has a build number of 9A406. This suggests that Apple fixed some minor errors and bugs but the details were still unavailable.

According to a report from MacRumors, Apple was able to fix the annoying SIM card issues that plagued the iPhone 4S users. This is based on the new support document. Some iPhone 4S users reported that they receive an error message that says, "No SIM Card Installed" or "Invalid SIM" on their new iPhone.

According to the report, the update affects 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.

The new Apple support document provides details about the issue:

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.

The support document also explained how iPhone 4S users experiencing SIM Card issues will be able to fix the problem. Users need to back up their content and settings using iTunes or iCloud storage system then restore the handset using iTunes. After the process is complete, you can now retrieved your contents and settings from your back up. To confirm that you've successfully restored, verify that the version is now iOS 5.0.1 (9A406) in Settings > General > About.

MacRumors reported that some users said that the tweaked version of the iOS 5.0.1 fixes the SIM Card issues while there are still some users experiencing the annoying problem.