Expected Response by Broadcom NFC Stack for Read Bianry Based Presence Check

Question

We ran into Read Binary presence check bug on Broadcom NFC stack. Samsung S4(4.2.2) is sending random read binary commands 00 B0 00 00 01. I have no flexibility to move to Android 4.4 with reader mode API support that allows delaying presence checks. My specific question is what response is expected by NFC stack on Android device that usage Read binary based presence check?

Will it be safe to implement a specific response to these read binary commands to gracefully execute a command response sequence?

To avoid selection of Tag application we are already returning 6A82 (Application not found)

Answer 1

In general, you can respond with whatever response code you want, as long as you send a properly formatted response APDU. Typically you would want to send a negative response code, e.g.

• 0x6986: Command not allowed (no current EF)

Of course if you use the READ BINARY command as part of your protocol, it could just as well happen, that the phone receives the first byte of the currently selected EF.