With the upgraded iOS 5.0.1, Apple successfully resolved battery issues for it’s iPhone 4S users. However, there had been issues about SIM card installation errors. According to MacRumors, the iOS 5.0.1 has come up with methods of how to fix “No SIM Card Installed” error on iPhone 4S.
Apple has released a new supporting document for users facing this problem of SIM card errors. So they needn’t wait for the next iOS version, the iOS 5.1, for their issues to be resolved.
Many users have been complaining about “No SIM Card Installed” warnings in their iPhone 4S. The Status bar displays “No Service” or “Searching” even in good network areas. Apple has provided a solution for this too. All you need to do is get back up and then restore your device. The iTunes pull down the new Build 9A406 of iOS 5.0.1 and install it on your device. You can get your content restored and settings from the back up later on.
How to Fix “Invalid SIM” Error on iPhone 4S
Back up your user content and settings using iTunes or iCloud.
Restore your iPhone 4S using iTunes.
After the process is complete, restore your user content and settings from your backup.
To confirm that you’ve successfully restored, verify that the version is now iOS 5.0.1 (9A406) in Settings > General > About.
Following the above given steps has shown positive results for some users while for others it hasn’t worked at all. So nothing can be decided as yet.