I have a Nexus 5 running Lollipop. I purchased some NFC chips to use as trusted devices. Usually the first time I access one of the chips it works just fine but the next time I access it it acts like it doesn't even exist. If I turn Smart Lock off and back on again then the trusted device works just fine, (one time).

Any idea what is wrong?

  • I have an nfcring and running cyanogenmod12 on lg g3. I have no issues with my nfc ring. The ring has 2 chips in it and i have both set up. They both work, i time after time. So if there is an issue, it may be with the nexus5 or with your nfc chips. Can you try a different set of chips. Like try another phone that has nfc. – Ryan Conrad Jan 6 '15 at 15:33
  • My wife and I both have the Nexus 5, and both have the same trouble. I've not tried the ring or another chip maker. (I bounce 12 chips from Amazon and they all behave in the same way. What is "cyanogenmod12"? Is that some sort of root? – MrMohr Jan 6 '15 at 17:21
  • Try using your wife's phone as the trusted device and see if it remembers it – Ryan Conrad Jan 6 '15 at 17:24
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    Good idea! I was thinking of buying an NFC ring, but don't want to waste the money if it won't be reliable. Thanks for the ideas! – MrMohr Jan 6 '15 at 17:26
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    Well, I can't believe it. The chip was at fault. I thought that since I could read the chip once, that the chip was not the issue. But a friend ordered some newer chips (from the same seller (whiztags), and they never have trouble unlocking my phone, and can be written to. My older tags cannot be written to. And once I scan one of the older tags, then all NFC tags fail! (Could still be a problem with the OS I guess). But for now the answer for me is newer chips. Old=NfcA. Newer chip is NfcA, MIFAREUltralight C, Ndef – MrMohr Jan 29 '15 at 17:26

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