I'm a noob and I think I just screwed my implant ;-;

Hi Everyone,

I am trying to set a write password on my xSIID NFC + LED implant but I am having a little trouble. I am using an iPhone so I have NFC Tools Pro and TagWriter.

I tried following DonFire’s instructions here, using NFC Tools’ Advanced command but when I send ‘‘1B444E4752’’ I get a 00 00 response. I tried twice now and got the same 00 00 and am afraid to try other potential passwords in case I reach a limit or something.

Could me trying to set a password using NFC Tools ‘Set Password’ or ‘Remove Password’ have messed up the chip in some way? I also tried to format the chip using TagWriter but that said NDEF formatting not supported for this tag.

I have tried looking through multiple boards for an answer so hopefully I am not asking a really common question. Let me know if you need screenshots of anything to help you diagnose.

Thank you~

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A couple of questions for you:

How long ago was you xSIID installed? If less than 2 weeks, you proabably want to wait until At LEAST 2 weeks have past before expecting consistent reading and writing ( There are exceptions, But that is a general “rule”)

Why are you trying to set a password?
It doesn’t use a password like “normal” i.e. you dont have to enter the password to “open” it.
Basically, these chips “want” to share their contents, anybody could tap their phone to it and read it. Even with a password set.
Is that what you are trying to prevent?

Have you tried writing an NDEF message to it with TagWriter or NFC Tools?

Erase and Format as NDEF, answer YES and try 888bytes

Then try writing a small NDEF message

If you are not aware, the xSIID has 2k storage, but only 1k is easily accessible

Let us know how you go


You’re getting back the password of acknowledgment. The PAK can be changed, but the default is 00 00.

I assume what you’re doing is just sending the authentication command by itself and nothing else. What this will do is authenticate your session, but then you end the session by removing the tag and don’t do anything with your authenticated session.

In his instructions, there are 3 lines. The first authenticates the session. The second one changes the AUTH0 byte which controls the memory page at which password protection begins. In this case he’s setting it to the first page of user programmable memory, meaning you need to authenticate first before you can make any changes to user memory.

Again, this authentication only lasts for the session. As soon as you remove the tag from the field, everything resets and you need to reauthenticate in order to make any appropriate changes covered by password protection.

The password itself is stored in memory page E5 and the last line is basically a simple write command that updates this memory with your new password of choice. Of course the password is four bytes in hex format.

There is a limit feature that will basically break the tag if you try to authenticate too many times. By default this feature is turned off but there are configuration bits in the configuration pages that can be flipped and enable this… so be careful.

Ultimately, you’re venturing into advanced territory. You should try to read the data sheet for the ntagi2c. Keep reading it over and over until it starts to make sense to you, then you should be able to understand how to interact manually with these tags by sending commands directly.


The question WHY? is still important.
What are you trying to achieve?

By changing the password, you are just protecting the configuration pages from accidental changes by yourself…or maliciously by somebody else, if that is a threat to you.

doc_ICODE-SLIX2-SL2S2602.pdf (485.3 KB)


I keep mine locked just for funsies, though I lock the whole tag, not just the config pages

I think they can be read-locked too, but I haven’t tried it personally. I don’t really see the use-case there


Ohh thank you! I was just super paranoid since I did an oopsie and wrote 00 00 00 00 to page 4. luckily i had made a copy of the nfc file with the flipper and i just took a gamble and wrote the original 4 and it works again.



So i was under the impression that since i can’t set a write password then anyone could just sneak up on me and lock the tag for themselves lol but now i know from you and the others that having the default settings should be sufficient for me. Thank you for your help! I also just wanted to know that if I did want to change anything do more advanced stuff in the future, I would be able to. As for right now I probably will not touch the advanced stuff anymore.

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Hi Pilgrimsmaster!

Yeah It is a little early as i just installed it like 3 nights ago so that probably explains why sometimes the read shows the contents and sometimes it doesn’t.

The reason I am trying or just trying to learn how to set a password is so no one else can set the password before me and lock me out of my own chip.

I have used both TagWriter and NFC Tools to write a link to the chip and it works great!

Using TagWriter I tried its format function but as explained in the original post, i just get that message and it doesnt let me do anything else. I am not too worried about this since it’s probably for the best that i can’t format it because knowing my luck it’ll probably mess something else up.

and yes thank you for reminding me :slight_smile:

Thanks for your time and help!


Yeah! I think this is what i had in mind, just lock it so no one else can lock me out of my own chip but not read-lock since the whole point of it is to let others read off of it.

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Yeah, NFC Shell, will allow you access to the “hidden” 1k

I think you are correct

Me either

Not unless you are really paranoid, or have something of great value stored on it.

Yeah, Sufficient for almost everybody, I would imagine 99+%

MOST people won’t even know you have an implant unless you tell them
MOST people won’t know where it is unless you show them
MOST people would struggle to read it without you knowing
MOST people wouldn’t know how to read the data
MOST people wouldn’t know how to access the “hidden” 1k or that it even existed
MOST people wouldn’t know what to do with what you have on it
MOST people wouldn’t care what you have on it

Well done you

Exactly, also be aware, the Blinky :blinky_blue: may take longer than the 2 weeks to see.

That is what MOST people do…often a http://dngr.us/rick