NeXT NTAG Bricked? _ Proxmark 3 won't detect

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1

Hi all!

First post so bear with me!

Had a NeXT implant installed a little over a month and recently began to play with it.

I’ve successfully cloned and read the RFID portion using my Proxmark 3 Easy (Iceman Firmware), working well after getting past a few kinks.

NFC was going well, until it wasn’t.

Had no issue reading the NFC tag with both my Flipper and phone for a few days, wrote maybe 20-30 records playing around in the NFC Tools app with my Android phone (zFlip4). Then, today, I tried to write some additional info, including WIFI SSID/PSK, and it appears there was a write issue.

I am no longer able to read the NFC chip with all but one app (will explain below) - I am prompted with themessaget of “Invalid Tag”. After going through the DT forums, I have tried to use multiple mentioned apps to read, erase, factory reset, wipe, etc the NFC chip - all say “Invalid Tag”:

NFC Tools:
NXP TagWriter
SNS NFC Tools
NFC.Cool

Now, I can still read the tag with my Flipper, and with NXP TagInfo, I am able to see all the info I previously wrote, including the new WIFI records which I believe stated this issue. This leads me to believe that the NFC tag is not bricked, but rather in an unhappy state and hopefully salvageable.

I’ve read through forums and have seen some info about wiping the NFC tag with the DT NFC tool, but I cannot find the app on android and the links in all forums are dead pages.

I have also tried to read the NFC chip with my Proxmark 3 Eazy with no success. Using many different versions of hf search, auto, type 1, type 2, type4a (which should be the NeXT implant) nothing is read.

Performing a hf tune, I found that I can get about a 2v drop at best and am very confident where the position of the implant is as well as the sweet spots of the Proxmark, so I don’t believe location or swelling is a factor at all.

Any insight is appreciated!

Most helpful thread so far, but I need more.

Thank you

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2

Can you go into NFCTools, and select “Advanced NFC Commands” under the “Other” tab?

Try to send a command like “30:00”, just to make sure the chip responds

If that works you should be able to manually overwrite the ndef portion that way, if no one else has any better ideas in the meantime :classic_smile:

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3

Hello!

Attempting to write the 30:30 in Advanced NFC commands within NFC Tools, I get the following error:

Error:I/O Failure, no NFC chip detected

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4

Are you positioning your chip in the right spot prior to hitting “send”?

5

I am indeed - using the assist-tags located in the NeXT kit and placing a sharpie mark on my phone where it reads best, along with many many testing runs, I’m very confident where it needs to be situated in order to scan.

I did notice that it seems like the Error: Invalid Tag popup I get on my phone almost seems like its coming from the phone itself, rather than the OS. Its the same popup no matter what I app I use. Going to try and scan from another phone this evening to isolate th phone being the issue.

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6

Used another phone and was able to read, erase and then format the NFC chip. I am now able to read the card with my original phone, though it does say password protected, but that’s a problem for another time.

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7

That shouldn’t be a problem.

Normally the password is set at the factory/ DT to protect the configuration bytes and not user memory.

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