From 9a2593d7d59c442afaf0f3fc2384fc1d9715addd Mon Sep 17 00:00:00 2001
From: Semaf Electronics <semaf@users.noreply.github.com>
Date: Sat, 1 May 2021 00:05:49 +0200
Subject: [PATCH] PCD_Authenticate last 4 bytes used

Thanks to @cyp-git
---
 src/MFRC522_I2C.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/MFRC522_I2C.cpp b/src/MFRC522_I2C.cpp
index 9c4675b..7baa85d 100644
--- a/src/MFRC522_I2C.cpp
+++ b/src/MFRC522_I2C.cpp
@@ -816,7 +816,7 @@ byte MFRC522::PCD_Authenticate(byte command,		///< PICC_CMD_MF_AUTH_KEY_A or PIC
 		sendData[2+i] = key->keyByte[i];
 	}
 	for (byte i = 0; i < 4; i++) {				// The first 4 bytes of the UID
-		sendData[8+i] = uid->uidByte[i];
+		sendData[8+i] = uid->uidByte[i+uid->size-4];
 	}
 
 	// Start the authentication.