diff --git a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/securitytoken/usb/CcidTransceiver.java b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/securitytoken/usb/CcidTransceiver.java
index d43c373d7..acb1ca9f4 100644
--- a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/securitytoken/usb/CcidTransceiver.java
+++ b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/securitytoken/usb/CcidTransceiver.java
@@ -80,7 +80,7 @@ public class CcidTransceiver {
             try {
                 atr = receiveRaw();
                 break;
-            } catch (UsbTransportException e) {
+            } catch (Exception e) {
                 // Try more startTime
                 if (System.currentTimeMillis() - startTime > TIMEOUT) {
                     break;
diff --git a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/securitytoken/usb/UsbTransport.java b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/securitytoken/usb/UsbTransport.java
index 037a23352..e1409f39e 100644
--- a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/securitytoken/usb/UsbTransport.java
+++ b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/securitytoken/usb/UsbTransport.java
@@ -30,6 +30,7 @@ import android.util.Pair;
 import org.sufficientlysecure.keychain.Constants;
 import org.sufficientlysecure.keychain.securitytoken.Transport;
 import org.sufficientlysecure.keychain.securitytoken.usb.tpdu.T1TpduProtocol;
+import org.sufficientlysecure.keychain.util.Iso7816TLV;
 import org.sufficientlysecure.keychain.util.Log;
 
 import java.io.IOException;
@@ -42,10 +43,9 @@ import java.nio.ByteOrder;
  * Implements small subset of these features
  */
 public class UsbTransport implements Transport {
-    private static final int USB_CLASS_SMARTCARD = 11;
     private static final int PROTOCOLS_OFFSET = 6;
     private static final int FEATURES_OFFSET = 40;
-    private static final int MASK_T1_PROTO = 2;
+    private static final short MASK_T1_PROTO = 2;
 
     // dwFeatures Masks
     private static final int MASK_TPDU = 0x10000;
@@ -77,7 +77,7 @@ public class UsbTransport implements Transport {
     private static UsbInterface getSmartCardInterface(UsbDevice device) {
         for (int i = 0; i < device.getInterfaceCount(); i++) {
             UsbInterface anInterface = device.getInterface(i);
-            if (anInterface.getInterfaceClass() == USB_CLASS_SMARTCARD) {
+            if (anInterface.getInterfaceClass() == UsbConstants.USB_CLASS_CSCID) {
                 return anInterface;
             }
         }
@@ -180,13 +180,35 @@ public class UsbTransport implements Transport {
 
     private void configureProtocol() throws UsbTransportException {
         byte[] desc = mConnection.getRawDescriptors();
-        if (desc.length < FEATURES_OFFSET + 4)
-            throw new UsbTransportException("Can't access dwFeatures for protocol selection");
+        int dwProtocols = 0, dwFeatures = 0;
+        boolean hasCcidDescriptor = false;
 
-        int dwProtocols = ByteBuffer.wrap(desc, FEATURES_OFFSET, 4).order(ByteOrder.LITTLE_ENDIAN)
-                .asIntBuffer().get();
-        int dwFeatures = ByteBuffer.wrap(desc, FEATURES_OFFSET, 4).order(ByteOrder.LITTLE_ENDIAN)
-                .asIntBuffer().get();
+        ByteBuffer byteBuffer = ByteBuffer.wrap(desc).order(ByteOrder.LITTLE_ENDIAN);
+
+        while (byteBuffer.hasRemaining()) {
+            byteBuffer.mark();
+            byte len = byteBuffer.get(), type = byteBuffer.get();
+
+            if (type == 0x21 && len == 0x36) {
+                byteBuffer.reset();
+
+                byteBuffer.position(byteBuffer.position() + PROTOCOLS_OFFSET);
+                dwProtocols = byteBuffer.getInt();
+
+                byteBuffer.reset();
+
+                byteBuffer.position(byteBuffer.position() + FEATURES_OFFSET);
+                dwFeatures = byteBuffer.getInt();
+                hasCcidDescriptor = true;
+                break;
+            } else {
+                byteBuffer.position(byteBuffer.position() + len - 2);
+            }
+        }
+
+        if (!hasCcidDescriptor) {
+            throw new UsbTransportException("CCID descriptor not found");
+        }
 
         if ((dwProtocols & MASK_T1_PROTO) == 0) {
             throw new UsbTransportException("T=0 protocol is not supported");
diff --git a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/securitytoken/usb/tpdu/block/Block.java b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/securitytoken/usb/tpdu/Block.java
similarity index 94%
rename from OpenKeychain/src/main/java/org/sufficientlysecure/keychain/securitytoken/usb/tpdu/block/Block.java
rename to OpenKeychain/src/main/java/org/sufficientlysecure/keychain/securitytoken/usb/tpdu/Block.java
index bfebd1934..1fe29b2a2 100644
--- a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/securitytoken/usb/tpdu/block/Block.java
+++ b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/securitytoken/usb/tpdu/Block.java
@@ -15,12 +15,11 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-package org.sufficientlysecure.keychain.securitytoken.usb.tpdu.block;
+package org.sufficientlysecure.keychain.securitytoken.usb.tpdu;
 
 import org.bouncycastle.util.Arrays;
 import org.bouncycastle.util.encoders.Hex;
 import org.sufficientlysecure.keychain.securitytoken.usb.UsbTransportException;
-import org.sufficientlysecure.keychain.securitytoken.usb.tpdu.BlockChecksumType;
 
 public class Block {
     protected static final int MAX_PAYLOAD_LEN = 254;
@@ -78,7 +77,7 @@ public class Block {
     }
 
     public byte[] getEdc() {
-        return Arrays.copyOfRange(mData, mData.length - mChecksumType.getLength(), mChecksumType.getLength());
+        return Arrays.copyOfRange(mData, mData.length - mChecksumType.getLength(), mData.length);
     }
 
     public BlockChecksumType getChecksumType() {
diff --git a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/securitytoken/usb/tpdu/block/IBlock.java b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/securitytoken/usb/tpdu/IBlock.java
similarity index 90%
rename from OpenKeychain/src/main/java/org/sufficientlysecure/keychain/securitytoken/usb/tpdu/block/IBlock.java
rename to OpenKeychain/src/main/java/org/sufficientlysecure/keychain/securitytoken/usb/tpdu/IBlock.java
index e7e9f8b51..8caa54ae8 100644
--- a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/securitytoken/usb/tpdu/block/IBlock.java
+++ b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/securitytoken/usb/tpdu/IBlock.java
@@ -15,10 +15,9 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-package org.sufficientlysecure.keychain.securitytoken.usb.tpdu.block;
+package org.sufficientlysecure.keychain.securitytoken.usb.tpdu;
 
 import org.sufficientlysecure.keychain.securitytoken.usb.UsbTransportException;
-import org.sufficientlysecure.keychain.securitytoken.usb.tpdu.BlockChecksumType;
 
 public class IBlock extends Block {
     private static final byte BIT_SEQUENCE = 6;
diff --git a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/securitytoken/usb/tpdu/block/RBlock.java b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/securitytoken/usb/tpdu/RBlock.java
similarity index 93%
rename from OpenKeychain/src/main/java/org/sufficientlysecure/keychain/securitytoken/usb/tpdu/block/RBlock.java
rename to OpenKeychain/src/main/java/org/sufficientlysecure/keychain/securitytoken/usb/tpdu/RBlock.java
index f0262257e..678b5e01e 100644
--- a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/securitytoken/usb/tpdu/block/RBlock.java
+++ b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/securitytoken/usb/tpdu/RBlock.java
@@ -15,12 +15,11 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-package org.sufficientlysecure.keychain.securitytoken.usb.tpdu.block;
+package org.sufficientlysecure.keychain.securitytoken.usb.tpdu;
 
 import android.support.annotation.NonNull;
 
 import org.sufficientlysecure.keychain.securitytoken.usb.UsbTransportException;
-import org.sufficientlysecure.keychain.securitytoken.usb.tpdu.BlockChecksumType;
 
 public class RBlock extends Block {
     private static final byte BIT_SEQUENCE = 5;
diff --git a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/securitytoken/usb/tpdu/block/SBlock.java b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/securitytoken/usb/tpdu/SBlock.java
similarity index 92%
rename from OpenKeychain/src/main/java/org/sufficientlysecure/keychain/securitytoken/usb/tpdu/block/SBlock.java
rename to OpenKeychain/src/main/java/org/sufficientlysecure/keychain/securitytoken/usb/tpdu/SBlock.java
index 18a66f548..9bf3fdc9d 100644
--- a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/securitytoken/usb/tpdu/block/SBlock.java
+++ b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/securitytoken/usb/tpdu/SBlock.java
@@ -15,7 +15,7 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-package org.sufficientlysecure.keychain.securitytoken.usb.tpdu.block;
+package org.sufficientlysecure.keychain.securitytoken.usb.tpdu;
 
 public class SBlock extends Block {
     public SBlock(Block baseBlock) {
diff --git a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/securitytoken/usb/tpdu/T1TpduProtocol.java b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/securitytoken/usb/tpdu/T1TpduProtocol.java
index 59e651a3f..fb86c8020 100644
--- a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/securitytoken/usb/tpdu/T1TpduProtocol.java
+++ b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/securitytoken/usb/tpdu/T1TpduProtocol.java
@@ -25,10 +25,6 @@ import org.sufficientlysecure.keychain.Constants;
 import org.sufficientlysecure.keychain.securitytoken.usb.CcidTransceiver;
 import org.sufficientlysecure.keychain.securitytoken.usb.UsbTransportException;
 import org.sufficientlysecure.keychain.securitytoken.usb.CcidTransportProtocol;
-import org.sufficientlysecure.keychain.securitytoken.usb.tpdu.block.Block;
-import org.sufficientlysecure.keychain.securitytoken.usb.tpdu.block.IBlock;
-import org.sufficientlysecure.keychain.securitytoken.usb.tpdu.block.RBlock;
-import org.sufficientlysecure.keychain.securitytoken.usb.tpdu.block.SBlock;
 import org.sufficientlysecure.keychain.util.Log;
 
 public class T1TpduProtocol implements CcidTransportProtocol {
@@ -107,7 +103,7 @@ public class T1TpduProtocol implements CcidTransportProtocol {
         byte[] responseApdu = responseBlock.getApdu();
 
         while (((IBlock) responseBlock).getChaining()) {
-            Block ackBlock = newRBlock(((IBlock) responseBlock).getSequence());
+            Block ackBlock = newRBlock((byte) (1 - ((IBlock) responseBlock).getSequence()));
             mTransceiver.sendXfrBlock(ackBlock.getRawData());
 
             responseBlock = getBlockFromResponse(mTransceiver.receive());
diff --git a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/securitytoken/usb/tpdu/block/BlockFactory.java b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/securitytoken/usb/tpdu/block/BlockFactory.java
deleted file mode 100644
index c64f2315c..000000000
--- a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/securitytoken/usb/tpdu/block/BlockFactory.java
+++ /dev/null
@@ -1,51 +0,0 @@
-/*
- * Copyright (C) 2016 Nikita Mikhailov <nikita.s.mikhailov@gmail.com>
- *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program.  If not, see <http://www.gnu.org/licenses/>.
- */
-
-package org.sufficientlysecure.keychain.securitytoken.usb.tpdu.block;
-
-import org.sufficientlysecure.keychain.securitytoken.usb.UsbTransportException;
-import org.sufficientlysecure.keychain.securitytoken.usb.tpdu.BlockChecksumType;
-
-public class BlockFactory {
-    private BlockChecksumType mChecksumType = BlockChecksumType.LRC;
-
-    public Block getBlockFromResponse(byte[] data) throws UsbTransportException {
-        final Block baseBlock = new Block(mChecksumType, data);
-
-        if ((baseBlock.getPcb() & 0b10000000) == 0b00000000) {
-            return new IBlock(baseBlock);
-        } else if ((baseBlock.getPcb() & 0b11000000) == 0b11000000) {
-            return new SBlock(baseBlock);
-        } else if ((baseBlock.getPcb() & 0b11000000) == 0b10000000) {
-            return new RBlock(baseBlock);
-        }
-
-        throw new UsbTransportException("TPDU Unknown block type");
-    }
-
-    public IBlock newIBlock(byte sequence, boolean chaining, byte[] apdu) throws UsbTransportException {
-        return new IBlock(mChecksumType, (byte) 0, sequence, chaining, apdu);
-    }
-
-    public RBlock newRBlock(byte sequence) throws UsbTransportException {
-        return new RBlock(mChecksumType, (byte) 0, sequence);
-    }
-
-    public void setChecksumType(final BlockChecksumType checksumType) {
-        mChecksumType = checksumType;
-    }
-}