Q: Any idea how to stop a 4S from constantly switching between home screen and black/Apple logo screen

Hello jimmeagan,

Thanks for participating in the Apple Support Communities.

It sounds like your iPhone 4s is repeatedly restarting, or showing the Apple logo screen.

According to this support document, first make sure your device is updated to the latest iOS version if possible, and then contact Apple Support for more help with this symptom:

If your iOS device restarts, displays the Apple logo, or powers off while you're using it - Apple Support

Make sure your iOS device is up to date. If you still see this issue after updating, contact Apple Support.

Learn what to do if your iOS device won't start up past Apple logo or doesn't respond.

You may also want to try restoring your iPhone from recovery mode:

If you can't update or restore your iPhone, iPad, or iPod touch - Apple Support

Note that this will erase your device and require restoring from a backup.

Sincerely,

Jeremy