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Hello, which is the name of this component for iPhone SE? First time with my broke iPhone when I tried to replace motherboard, this component has been removed from iPhone. Which is the function of this component? And is possible repair it with a something as the welder? Because I noticed it is attached to iPhone. Image of component:

Thank you in advance for reply.

That’s a teared off part of the wifi/bluetooth antenna. It’s a pretty inexpensive part but you’ll have to buy a new one. No need for soldering, it’s simply glued to the housing.

That’s part of the rear case. You can see it in this photo from the teardown, and this one too. To get WiFi/cellular connection, you’ll need to buy a new rear case, since the connector is permanently attached to it, and can only come off if the cable is torn. It looks like you can relatively easily get new (though not necessarily OEM) cases on eBay.