Help needed - Write a specific value on a specific sector (Mifare 1k)

Hi all,

Sorry if this is not the correct place to post this kind of question.

In short, I have a Mifare card, with known keys and need to write a specific value in a specific sector.

I’ve been doing this using a mobile app, but it’s time consuming.

Which documentation or samples can I use/study to accomplish this?

Basically, an app that:

Reads the card, shows current value (written on a known position), has the option to change the value with some user input and write again. Nothing else, seems simple IMHO.

I’ve been digging other apps and OFW, but I’m still a bit lost with the FZ Dev world :slight_smile:

Thank you.

For mifare classic 1k with the flipper you can just save a file of data from the tag itself, edit the dump to change the value you want and use the “write to initial” function to write it back, this doesn’t work for changing keys but for block content you’d be all set

What type gen is your copy card. What set up are using. Android phone, acr122u and rrgs rfid app can write to specific sectors.

That’s what I do with a specific Android app, it’s time consuming, reading the dump, hexedit it, save the dump.

My idea was a simple app to write that value with Flipper.

It’s a simple Mifare Classic 1K 4-Byte, Gen1 card.

I don’t need to copy or crack anything. I have the keys and just need to modify some bytes in sector 10.

Currently, I’m using Mifare Classic Tool on Android to read the card, hexedit the dump, save the card again, it’s time consuming.

The main idea would be to read it with flipper, display current value, change, write again only sector 10.

Which sector? Writing to sector 0 is tricky. Other sectors are easy.

Ah nevermind… sector 10… a proxmark3 script could be made? Or maybe an Android app?

Do you even need the current value displayed or are you writing the same value to the same spot in the sector each time? I’m basically asking if you need to make arbitrary changes each time or the same exact data each time?

Yes, displaying current value would be nice. Value can be arbitrary, otherwise I would just save the dump and rewrite it everytime I need it using the OFW tools.

My Google foo is failling me, I was able to find multiple examples of writing my first Flipper Zero app, but none about Mifare reading/writing. :expressionless: