I thought the S2 had NFC anyway. I'm pretty sure my Dad's does.

Back to your question...if your phone didn't have it before, chances are it probably won't with the extended battery. Has to have contact points for the NFC antenna (located on the battery) to transmit/receive back to the phone. Also would have to have the feature enabled in the software, which would be easily accomplished in a custom ROM if not already enabled. But the hardware has to be there first and it's more than just the battery.

 

Not sure which model you have, but check this out

How to Enable NFC on Samsung Galaxy S2 Running Jelly Bean [GUIDE] - International Business Times UK

Appears it is easily acheivable with Root and a custom ROM if your model has the hardware.

 

The Samsung Galaxy S2, GT-i9100P, variant has NFC capability. The Samsung Galaxy S2, GT-i9100, doesn't, by default, I'm afraid.

However, I'm wondering if flashing the, "P", variant firmware to your phone, "might", enable it.

 

I've no idea on this, but my thoughts are that nfc would require different hardware. If it could be enabled at the software/firmware level then it wouldn't have been suppressed in the first place, or at the very least there would have been a mod to do this by now.

 

No. Says so plainly in the article I posted. The P variant has different hardware that allows for NFC. The other variant does not have the hardware and is therefore not able to via a software/firmware update.

Sorry bud.

 

I have trouble with my i9100p battery. Please tell me where did you buy nfc battery?