Ultralight C, Smartcardio and ACR122

Question

I'm developing in a Java project with a PS/SC ACR122U with the library SmartCardIO. When I put a password and modified the page 0x2A, I am trying to read again the tag. Indeed, I know the protocol and I found here (http://www.eps.no/downloads/pdf/API_ACR128_v1.9.pdf) the APDU Command is:

FF 00 00 00 02 1A 00 

But when I introduce that APDU I get an exception with message:

apdu must be at least 2 bytes long

However I'm using a tool called ACE122U Tool where I can send APDU Commands to the Tag and I can see how it answers me. So when I send the command before the tag doesn't answer.

I don't know how can I resolve it, any ideas?

Answer 1

Incredible, I posted the problem and looking again for a solution, I found the solution. Naturally, the APDU Command was wrong. The command is:

FF:00:00:00:04:D4:42:1A:00