diff --git a/src/fr/anssi/smartpgp/Constants.java b/src/fr/anssi/smartpgp/Constants.java
index b3c0f80..2ee1107 100644
--- a/src/fr/anssi/smartpgp/Constants.java
+++ b/src/fr/anssi/smartpgp/Constants.java
@@ -30,7 +30,7 @@ public final class Constants {
     protected static final short INTERNAL_BUFFER_MAX_LENGTH =
         (short)0x500;
 
-    protected static final short APDU_MAX_LENGTH = (short)256;
+    protected static final short APDU_MAX_LENGTH = (short)0x400;
 
     protected static final byte[] KEY_DERIVATION_FUNCTION_DEFAULT = {
         (byte)0x81, (byte)0x01, (byte)0x00
@@ -149,7 +149,7 @@ public final class Constants {
         (byte)0x73, /* card capabilities */
         (byte)0xC0, /* 1st byte: "methods supported" see ISO 7816-4 */
         (byte)0x01, /* 2nd byte: "data coding byte" idem */
-        (byte)0x80, /* 3rd byte: command chaining (not extended length by default as all readers do not support them...) */
+        (byte)0xC0, /* 3rd byte: command chaining + extended length */
 
         (byte)0x05, /* status indicator byte : operational state */
         (byte)0x90, /* SW1 */
diff --git a/src/fr/anssi/smartpgp/SmartPGPApplet.java b/src/fr/anssi/smartpgp/SmartPGPApplet.java
index c47870f..78d446d 100644
--- a/src/fr/anssi/smartpgp/SmartPGPApplet.java
+++ b/src/fr/anssi/smartpgp/SmartPGPApplet.java
@@ -25,7 +25,7 @@ import javacard.security.*;
 import javacardx.apdu.*;
 import javacardx.crypto.*;
 
-public final class SmartPGPApplet extends Applet {
+public final class SmartPGPApplet extends Applet implements ExtendedLength {
 
     private final Persistent data;
 
@@ -104,7 +104,7 @@ public final class SmartPGPApplet extends Applet {
         short blen = apdu.setIncomingAndReceive();
 
         final short lc = apdu.getIncomingLength();
-        final short offcdata = ISO7816.OFFSET_CDATA;
+        final short offcdata = apdu.getOffsetCdata();
 
         short off = transients.chainingInputLength();
 
