Fido2 Installation on Flex fails

I am testing my Apex Flex through the plastic wrapping ahead of the implantation and I am having the following issues:
Getting a read with my iPhone is really really hard. I can only get a reading (and not reliably) if I take the phone out of its case. Is this normal?
It is not a thick case so I am kinda expecting it to not work through my skin, even while taking the phone case off.
The Fido 2 applet just cannot be installed. I tried many times and it always fails, both with my iPhone and an old Android phone (Android 8) I tried using…
If I install Spark and try using the Spark app I get the “Missing Required Entitlement” error on scan.
If I use the VivoKey app it tells me “Reading error, see help for tips.”

I am refraining from putting this into my body until I figure out how to use it, if anyone can point me the right way I would be quite grateful. I also ordered a USB NFC reader in addition to my Proxmark 3 Easy and Flipper Zero, but I am guessing I cannot fully substitute the smartphone features with it.

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I was also just able to deploy fido2 on iOS.

If I had to guess I’m pretty sure it has to do with coupling and maintaining a good coupling during deployment. It takes a while.

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Weirdly enough I was able to install nearly every other app other than Fido2.
I even uninstalled everything and tried again just in case it was the space, but it did not help.

Does Fido2 require a lot of space or can I fit pretty much all of the applets at once? I cannot install the manager on the Android (too old) and there is not an iPhone version so I have no idea how much space I have.

Thank you for the placement guide, this is nearly identical to what I ended up doing. The thing is with the iPhone 14 I get a sizable camera bump covering the middle of the coil, so I need to move the chip a bit to the left and get a worse coupling, it definitely cannot go through both the cover and the plastic, so I guess it won’t go through both the cover and the skin.

Hopefully once it is under my skin I will figure something out experimenting.

My biggest issue is the Fido2 App. It gets a coupling, installs for a long while and the “hold on” apple window pop-up window covering the Fidesmo app disappears while the Fidesmo app still says “Hold on” and then the installation fails with the following error message:

“Installation failure. You may not have enough free space for the Fido2 applet and the attestation certificate. You might consider removal of another app to create more storage space.”

I might try again, but I already tried removing everything else and it still gave me this exact error. I see this in the logs:
Delivery Finished: ServiceStatus(success: false, message: FidesmoCore.Translations(content: [“en”:“You may not have enough free space for the Fido2 applet and the attestation certificate. You might consider removal of another app to create more storage space.”]), scriptStatus:nil, extraInfo: nil, clientMetadata: nil)
Above that there is a metric shitton of HEX data and lots of transfer of data to server and device.

I guess I will try uninstalling every single app again to see if I can fit it then.

hmm… what version of fidesmo app do you have on your phone? can it be updated?

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Just unistalled everything and tried again, still got the error message about no free space on the chip despite there being only a link applet (helps get a feeling for the right position if I get the prompt to open a website when I get the chip close to the phone.)
Is this coupled with the errors I get from the Vivokey and Spark apps a sign that something is not right?

Fidesmo app version 2.11.0., no update available on the App store.

EDIT: I have successfully installed and uninstalled all applets except the Fido2, which really cannot get installed.
EDIT2: Does the Fidesmo Go: Nordics applet take up space? Apparently after installing it just to test if it installed successfully I have no option to delete it now…
EDIT3: Nevermind, removed the app with manual codes from another thread.

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This is just a generic error message for app installation failure. It comes from our script for the application and it’s just our “best guess” as to why an applet may fail to install. We can’t actually determine, via the facilities provided by Fidesmo, if there is actually space or not.

What version of iOS are you running on your iPhone 14 pro? I will try to submit a ticket. If you can provide a log file of the logging data (attach as txt file) I will send it all to Fidsemo to get an opinion / support.

Here are the logs… A lot of them since I did a lot of testing.
log.txt (2.4 MB)

Is there any way to get a reading without taking the case off of an iPhone 14? I kinda start thinking that I should have gotten the Mega instead after all.

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On my Apex Flex I get a great reading through a wallet case + drivers license on my Pixel 8. I think the iPhone coils may have worse performance though.

But because you were able to deploy every other applet, my gut says it’s a software bug rather than a range/performance issue. Maybe try deploying it on a friends Android phone?

yeah, but with your thorough testing, I dont think that is your issue.

That would help, Is it still unopened inside the outer bag? Im not quite sure on Amals return policy, but you could ask to pay for a upgrade swap :man_shrugging:

I wouldn’t blame him if he said no though.

I do have another suggestion / solution for you to try for pretty cheap.
Give me a sec to put it together.

the best you can do is slowly and carefully try different orientations to see which is best.

it’s more about having a shape and performance profile that is ill-matched to the flex antenna shape. iPhone works great with cards and other tag types, and even x-series if held correctly.

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DT Club members get special treatment. If you want to exchange, reply to your order email and we’ll sort it out.


I have an Apex Flex and currently an S21+, It used to read OK, a bit of lining up, then muscle memory lead to faster and easier reads, I made a resonant repeater coil that lived between my phone case and phone, this improved my reading noticibly, I then modded it to a different form factor ( irrelevant to this discussion ) but it wasn’t tuned particularly well, so it didn’t perform as well as I had hoped.

Here’s a few examples if you want to go that path

Then @hamspiced made these

Here’s the video

I HIGHLY recommend these, I had noticeable improvements on the ones I made, but @Hamspiced ones are even GOODERER. When reading my ApexFlex, it’s simply…simple

Here’s his Tinide store for a fully built and tuned one

  • The only thing I am not sure of is, due to the iPhone NFC antenna location, I’m not sure if they will work or fit well in the iPhone case :man_shrugging:
    I’m not sure if @hamspiced can test that for you (I don’t have an iPhone or access to one or I would do it myself) , but I think he has a Pixel, but MAYBE access to an iPhone?

If not, maybe a make your own:
What may fit better in the iPhone is something like one of these

and a 22pf capacitor

Pretty cheap solution

NB: You might get lucky with the tuning, or you may need a VNA., which makes it mor expensive than just buying a #HammyResonantRepeaterJammy™

Anyway, just some thoughts and options for you to consider

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I don’t advertise my tindie page especially the resonant repeater project since it was 100% inspired by this forum and the work done by other members here. As a result of you read my profile I have a standing offer code for 50% off any DT member. However if someone reaches out to me with interest in one through the forums if I have extras I’ll send one out. I can’t ethically charge the members here for something that they essentially helped make. And considering it costs me pennies, a forever stamp isn’t going to break the bank.


I don’t say this lightly.
The highest complement from Down Under

@Hamspiced You’re a good cunt


Would you be interested in making a larger batch run of these for sale on DT?


I would like to have the V2 version completed. One that has the antenna built in as a trace. If i can get a working version completed back from jlcpcb im going to do a large order. I already had planned to shoot 100 or so your way once i get it properly working.

Let me get my house in order and DT will be the first to get a batch. when i do panelized orders from jlcpcb i usually do 500 unit runs (at least with the Flipper RGB Mods i do). So ill have plenty.


I’ve had coupling issues with the Apex Flex in my right arm while the case is on my iPhone and would love to get one of those NFC amplifiers. I’d want one at full price regardless, but I’ll take a discount if you’re offering :smile:

Nevermind about the discount code. I just realized that you might have been referring to people who pay the regular subscription to DT. I just have some DT implants. I went ahead and bought one though. I’m really excited about the prospect of being able to better couple with my Apex Flex :smile:

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I don’t believe so, im pretty sure he means ANYBODY here on the forum.