Changing NFC Files

I want to decode the .nfc files you get when you scan something and change the number or value of something, is that possible? Sorry, im new

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Save the file.
Download the file from SD Card/NFC.
Open it with a text editor.
Save it back on the Flipper.

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How am I supposed to know what (for example) CD 4C 61 C2 6E 3D 7C 37 88 00 31 C7 61 0D E3 B0 means

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That’s a good question. First off recognize that we are dealing with HEX or Hexadecimal. Instead of decimal.
Decimal: 0123456789
Hex: 0123456789ABCDEF

The Flipper is arranging those number into sets of 2. 00 = 0 and FF = 255. Looking at your code I see what might two set of 8.
CD 4C 61 C2 6E 3D 7C 37
88 00 31 C7 61 0D E3 B0

or 4 sets 04 four.
CD 4C 61 C2
6E 3D 7C 37
88 00 31 C7
61 0D E3 B0

or possibly some mixed arrangement. The trick is to figure out how much data is in each field. Then you can determine what all these pieces are. Since I can’t see what fields are on your card I will for the sake of this example assume 61 0D E3 B0 is a card number. I’ll remove the spaces.
610DE3B0
Then run it through a Hex to binary converter.
That would mean the card number is 1628300208.

Now let me change that number to 1548569258. Now I’ll convert it back to HEX using the same converter which give us 5C4D4AAA. Now I’ll add the spaces back and replace the old Hex value with the new one. Here is our edited code.
CD 4C 61 C2 6E 3D 7C 37 88 00 31 C7 5C 4D 4A AA

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