13.56mhz works intermittently

I am trying to make a duplicate key for my own apartment. They charge $70 a key which is ridiculous so of course I bought a $200 device to make my own.

I have successfully copied a key to my old apartment and my new apartment (I just moved across the hall). However, when I moved into the new apartment, the NFC copy did not work. They made a change to the key for an unrelated reason and I was able to get it working by starting the process over again. They had to make ANOTHER unrelated change and I started the process from the beginning again and now it won’t work again.

I go to NFC, read the key and save it. Then go to the saved key and detect reader then use Mfkey32. I’ve tried cracking the nonces on my computer and on my phone. When I try to do it on the flipper, it crashes.

Does anyone have any tips on what I might be missing or what I could try? Pulling my hair out trying to figure this out and have given up.

Thank you so much!!!

You could try an older firmware. I heard there were some issues relating to NFC. I can’t remember which firmware versions that effects though.

Thank you! I just realized it is not picking up all the keys. It says 4 out of 32 found. I’m not sure how to force the extra ones. I did notice that the key read performs MUCH faster when it picks up more of the keys. I was successful before with 30 or 31 out of 32 keys. Not sure how to get there though, been looking through some other posts.

There is one place that says to add these keys to the user dictionary or add custom keys: https://github.com/ikarus23/MifareClassicTool/blob/master/Mifare%20Classic%20Tool/app/src/main/assets/key-files/extended-std.keys

But there are a few people asking how to actually do that and no one responded.

Could that help? Does anyone know a link to something that shows how to add keys to the user dictionary? Not sure why this is so hard to find.

Thank you again for any help. <3

Just add the keys to “nfc/assets/mf_classic_dict_user.nfc” file at Flipper’s sd-card.
One key per string.