Inconsistent LF reads

Hi everyone!

Sorry if this is a common question, but I couldn’t find much info on the specific readers I’m trying to use while searching.

I had a NExT installed by my sister-in-law about 12 days ago. She is a nurse and the install seemed to go really well, with only a little pain as the needle broke the skin. It did seem to take a lot of pressure to get through and she commented that my skin seemed very thick. At this point I don’t have any visible bump from the implant, regardless of how many ways I try to contort my hand. If I relax my hand, and feel around a little I can usually barely feel a small bump. It’s pretty much dead center between my index and thumb bones and parallel to my index finger. So placement seems perfect, but possibly a little deep.

Now I’m a little confused by the inconsistency of the reads I’ve been having. I’ve been using NFC Tools Pro to program the HF side. I can get pretty easy reads even with the case on my Samsung Z Fold 5. For the LF side I’m using a FlipperZero for programming. The Flipper gets consistent reads, but I do have to search around a little sometimes. I can always find the HF side much faster than the LF side when using the Flipper. Overall I’m fine with the performance for those two devices, but from what I’ve read it seems odd that the HF side reads better.

The issue I’m running into is with the readers at my job. I’ve been using a T5577 sticker on the back of my phone as a fob for months, so I know the chip is compatible. There are two different kinds of readers around the building - Honeywell and HID multiCLASS SE.

The Honeywell readers I can make work using the swipe method, but it usually takes more than one attempt. The HID reader I have only been able to get one successful read on. I tried multiple other HID readers in the building and couldn’t get any them to read either. The weird part is I get a different story from the LF X Field Detector. On the honeywell readers, I can’t get the LED to light up at all, no matter what orientation or location I use. The HID readers give me a nice bright LED in multiple locations and orientations. So it would appear the HID reader is better, but thats the one I can’t get to work at all.

I hope I’m just being impatient and need to wait for more healing to happen, but should I have any concern with the implant or install? Are there any methods I’m missing to get the HID readers to work and get the honeywell readers to be more consistent?

Thanks for your help!

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Have you tried using the xfd keychains with the readers at work to determine the best orientation and location to present your NExT?

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Congrats on the install!!

It may just be still healing and get better over time, but there’s always going to be an adjustment period of hitting the reader the right way every time. I definitely had inconsistent reads until got used to the readers at my old apartment with my NExT. It took a lot scans before I could get it to read on the first attempt 9/10 times.
As for the Honeywell readers, I’m not too sure.


Yep! Sorry my first post was long, so I can see it being easy to miss that part. The xfd seemed to give me even more confusing results. When I try to use the NExT in the same location and orientation as the xfd, I still can’t get a read. I also tried presenting and slowly swiping over the hotspots I found with my hand in different orientations.

My xEM was like this almost exactly as your describing. It healed great and works amazingly with most readers now. It looks like you’ll be fine. I think mine was fully healed and worked the best at about 2 to 3 weeks in.


Great post, as I read it, I had precomposed answers to give you, then the next sentence you already answered yourself. (swipe, duty cycle, xFD, diagnostic card, test with “sticker”…)
Probably the most important of the lot


give ot another week or 2
you should be FULLY healed and your reads should be consistent.

The fact you have had a read on both readers is a really good sign.

It sounds like your install went well, it looks good and is healing well.
It MIGHT be a little deep, but, when it is fully healed you will have a better idea.

Did you video the install perchance?
Thats a good way to get an indication of depth from the install angle?


My work has the same HID readers. Might be worth checking if it’s also looking for HF tags, might be picking up the HF side of your NExT and ignoring the LF. It would beep regardless of the tag being registered or not tho so you would probably notice if that was the case.

Besides what has already been mentioned by yourself and Pilgrimsmaster in terms of waiting to heal, I can tell you that I’ve found the sweet spot for my xEM to be just above the HID logo. Took me a few weeks to get consistent reads on these HID readers but now it’s very consistent.


Ditto to what @Ditto said

Nothing further productive to add, I just wanted to Ditto Ditto



With regards to the reader

Try to find a break down, or better yet, pull one apart yourself.check put yhe antenna location so you can find the best way to approach it

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Thanks for all the great info! Its really good peace of mind to hear some of the similar experiences that got better after healing. I meant to get a video of the install, but completely forgot after we got everything ready. I’ll be sure to get a video of the next one though! It sounds like the general consensus is I’m being a little too eager with the healing process. I’ll keep stealing my wife’s pre-natals for a few more weeks and see if things improve.

If there are still any issues at that point, I have already been eyeballing the flexMT. I work in concert and event lighting and the magic 1k would be nice for putting festival tags on. Not to get too off topic for this thread, but have there been any updates on improved LEDs for those?



Nah, not really, we all generally say 2 weeks, but some more picky readers need a bit less fluid between the implant and antenna, you’re still healing, i’m pretty confident once you are healed and have learnt the best approach to the reader, you’ll be swiping more easily than a Tinder addict

Wow, Thats a big bitch, however the read range is phenomenal, both HF and LF.

The FlexM1 is the middle ground, with regards to size and performance but it lacks the LF component.

Not as far as I am aware, the nail stickers are just not robust enough, so until an alternative is found, there won’t be any “add ons” to existing implants, There are a few others in the works with built in blinkies, but currently, it’s just the xSIID and xLEDs on offer.

The NExT2 shouldn’t be too far away from release, but I can’t give you a date on that.

The Apex Mega with blinky had some power harvesting “issues” ie. all blink, not a lot of talk.
The LED implant business is a complicated wee fucker

Haha, you’re new here, If you didn’t derail your own thread, we probably would have…It’s kinda our thing


Again, thanks for how helpful everyone has been!

This sounds like my kind of forum then! I’ve seen people loose it over off topic questions on other forums.

My left kidney used to be a stone collector, so I’m pretty comfortable with dealing with more painful recoveries. My high score was 15 stones at once! The range is definitely one of the big things that got me looking into them. With the amount of reads I do daily at work and reading at festivals in a line of people, having something very quick and reliable would be handy.

That said, I have an update! It turns out I was just a few days early with the healing. Today I’m able to get consistent reads on both readers relatively easily. Now I’m running into a new problem though. The honeywell readers are LF only, so they work perfectly fine. The HID multiclass readers on the other hand, are dual frequency. It seems like they only want to pick up on the HF side of the NeXT. If I move the NExT over the reader slowly so that the LF coil reaches the field first, I can sometimes get a LF read. Even then it takes about 10-15 attempts.

I’ve read a few other threads that have talked about this issue and some people mentioned they have been able to get reliable scans with practicing their presentation. Does anyone have more detail on how they’ve been able to make this work?

I also saw that some readers are able to disable the HF side. Since we have a mixture of dual frequency and LF only readers, everyone has LF fobs only. So disabling the HF side shouldn’t be an issue if its possible on those specific readers. Is this something that can be applied to all readers from software or would they need to be individually set? I just want to have an idea of how much I’m asking before I try to get our maintenance director to try to dive that deep in the software.

The other option I was thinking of is possibly asking if the UID of my next could be added as a fob. Then I would just use LF on the LF readers and HF on the dual. I know cloning most HF keys to the NExT isn’t possible, but would getting the UID added work even if I have other NFC records on the implant?

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Good plans… don’t know how about globally setting reader configurations… probably depends what software is being used.

The UID of the ntag216 in the NExT is separate from the user memory space where NDEF records live, so it should not be any issue.

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Fucken AWESOME !!!

I don’t know you, but I already like you; Again your post has questions and researched answers

As with your first post, as I read, I had precomposed answers, then the next sentence you have the answer.

This is possible, but difficult for us to tell you how without knowing the software, but likely relatively straightforward

Again difficult without seeing the software, but my GUESS is software SHOULD control them all, If physical, I IMAGINE it’s probably just a dip switch on each reader.

THIS is probably the easiest option of all, where normally the most difficult part is convincing the system administrator, but it sounds like you might have that sorted.

No problem as per Amal’s answer above.

Again great job on your research, I do have a couple more answers and suggestions for you though.

You have succesfully found the HF antenna by doing what I suggested above, and the occasions you have had a read on the LF was probably between duty cycles of the HF.

A couple of easy things to try

  • Using your LF xFD, you should be able to find the LF antenna location. Plus you will see the Duty cycle ( This part could also be done with the diagnostic card), this will tell you what speed you need to present to allow a read.

  • It is unlikely that the HF and LF antennas cross, SO, if you are swiping fow outside in and get HF reads, you could try presenting to the middle and slowly swiping outward…UNLESS your LF xFD tells you otherwise.
    Not the best example here visually, But this is my desktop reader, originally the LF copper antenna was in the middle, I moved it sideways, for “reasons
    It is unlikely your reader antenna layout will look like my modded reader, but more like the original, “antenna within antenna”

  • This is also where a tear down of a reader would be beneficial
    Pull one apart, or find images online of where the LF antenna is

Another simple option would be to just get a dedicated xEM or even better since you don’t mind the pain and recovery time, a FlexEM for those readers


@Pilgrimsmaster Thanks for the compliments! I tried swiping from the middle and swiping any hot spot I could find with the xfd and still had no luck, but there is still good news! After a fun conversation with our access system admin and some playing around in the software, my NExT is working on both readers!

The software side was a little confusing to get setup, but for anyone else that is having this issue on a LenelS2 system, here is how I got it working:

Go to credential formats and add a new format. The setting should be as follows:

Data Format: Wiegand
Length: 32 (I think this could technically be up to 64, but 32 works fine)
Facility Code: 0
Facility Code Start: 0
Facility Code Length: 0
Encoded # Start: 1
Encoded # Length: 32
Hot Stamp and encoded numbers default identical: Checked
Mercury-supported: not checked
Casi F2F: not checked
The 32 drop down boxes below that should automatically all change to “N”
Remeber to check the Enabled box at the top and press save!

At that point you can add the credential just like any other. Just make sure you select your newly created format.

I didn’t test it, but theoretically you could change the “Encoded # start” to a number after 144 and have a cloneable tag. From what I understand of the credential formatting, you can tell it to ignore the first 144 bits and then read the NFC records instead. I’m definitely no expert on the formatting of those records, so selecting start bit that makes sense might take some trial and error. I could also be wrong about the 144 bits. I got that number by writing records to the tag a few times and comparing the raw HEX digits to see what changed and what didn’t.

Out of curiosity, can anyone explain some of the raw data when reading an ntag216? I noticed the UID is only 14 HEX digits, but when I view the raw data there are an extra two digits in the middle? After that there are 20 HEX digits that don’t seem to change when writing different data on the tag. Are those just formatting bits for the reader? Kind of like a master boot record on a hard drive?


I don’t know why I didn’t think of this before, but I downloaded the datasheet for the ntag216. For a datasheet it actually does a really good job at explaining what everything does.

It looks like setting the access controller to read 32bits is actually reading the check bits as well. Considering these can’t be changed either, that seems like it should be perfectly safe.

Based on the data sheet if you wanted to read bits that are re-writeable for an access controller, you could actually use anything after 128 not 144. Are the bits between 128-144 still some kind of file structure information? It seemed odd that I didn’t see a change in those bits after writing different information.

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If you’re talking about page 03 (the capability container), this is a kind of application indicator - what the user memory is meant to be used for. When using the ntag216 as an NFC compliant transponder, the capability container requires a specific format… you can read the capability container section of the spec doc for more info.

In addition to that, these bytes specifically are OTP - one time programmable… meaning any 0 value bits, once flipped to 1, cannot be flipped back to 0.

If it wasn’t obvious, I also want to point out that iso14443a compliant rfid transponders can also be NFC compliant (according to the NFC forum spec), but not all of them are. Case in point the mifare “classic” 1k chips… these are iso14443a compliant but not NFC compliant.

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