diff --git a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/securitytoken/OpenPgpCommandApduFactory.java b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/securitytoken/OpenPgpCommandApduFactory.java
index 5fa4f93e9..1ffbb72f7 100644
--- a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/securitytoken/OpenPgpCommandApduFactory.java
+++ b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/securitytoken/OpenPgpCommandApduFactory.java
@@ -28,7 +28,9 @@ import org.bouncycastle.util.encoders.Hex;
 
 
 public class OpenPgpCommandApduFactory {
-    private static final int MAX_APDU_NC = 255;
+    // The spec allows 255, but for compatibility with non-compliant tokens we use 254 here
+    // See https://github.com/open-keychain/open-keychain/issues/2049
+    private static final int MAX_APDU_NC = 254;
     private static final int MAX_APDU_NC_EXT = 65535;
 
     private static final int MAX_APDU_NE = 256;
@@ -134,8 +136,7 @@ public class OpenPgpCommandApduFactory {
 
     @NonNull
     public CommandApdu createDecipherCommand(byte[] data) {
-        return CommandApdu.create(CLA, INS_PERFORM_SECURITY_OPERATION, P1_PSO_DECIPHER, P2_PSO_DECIPHER, data,
-                MAX_APDU_NE_EXT);
+        return CommandApdu.create(CLA, INS_PERFORM_SECURITY_OPERATION, P1_PSO_DECIPHER, P2_PSO_DECIPHER, data);
     }
 
     @NonNull
diff --git a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/securitytoken/operations/PsoDecryptTokenOp.java b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/securitytoken/operations/PsoDecryptTokenOp.java
index 3a2a8307d..4fde33d14 100644
--- a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/securitytoken/operations/PsoDecryptTokenOp.java
+++ b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/securitytoken/operations/PsoDecryptTokenOp.java
@@ -25,6 +25,7 @@ import java.security.MessageDigest;
 import java.security.NoSuchAlgorithmException;
 
 import android.support.annotation.NonNull;
+import android.support.annotation.VisibleForTesting;
 
 import javax.crypto.Cipher;
 import javax.crypto.NoSuchPaddingException;
@@ -43,7 +44,6 @@ import org.sufficientlysecure.keychain.securitytoken.CardException;
 import org.sufficientlysecure.keychain.securitytoken.CommandApdu;
 import org.sufficientlysecure.keychain.securitytoken.ECKeyFormat;
 import org.sufficientlysecure.keychain.securitytoken.KeyFormat;
-import org.sufficientlysecure.keychain.securitytoken.KeyType;
 import org.sufficientlysecure.keychain.securitytoken.ResponseApdu;
 import org.sufficientlysecure.keychain.securitytoken.SecurityTokenConnection;
 
@@ -84,14 +84,7 @@ public class PsoDecryptTokenOp {
     }
 
     private byte[] decryptSessionKeyRsa(byte[] encryptedSessionKeyMpi) throws IOException {
-        int mpiLength = getMpiLength(encryptedSessionKeyMpi);
-        if (mpiLength != encryptedSessionKeyMpi.length - 2) {
-            throw new IOException("Malformed RSA session key!");
-        }
-
-        byte[] psoDecipherPayload = new byte[mpiLength + 1];
-        psoDecipherPayload[0] = (byte) 0x00; // RSA Padding Indicator Byte
-        System.arraycopy(encryptedSessionKeyMpi, 2, psoDecipherPayload, 1, mpiLength);
+        byte[] psoDecipherPayload = getRsaOperationPayload(encryptedSessionKeyMpi);
 
         CommandApdu command = connection.getCommandFactory().createDecipherCommand(psoDecipherPayload);
         ResponseApdu response = connection.communicate(command);
@@ -103,6 +96,19 @@ public class PsoDecryptTokenOp {
         return response.getData();
     }
 
+    @VisibleForTesting
+    public byte[] getRsaOperationPayload(byte[] encryptedSessionKeyMpi) throws IOException {
+        int mpiLength = getMpiLength(encryptedSessionKeyMpi);
+        if (mpiLength != encryptedSessionKeyMpi.length - 2) {
+            throw new IOException("Malformed RSA session key!");
+        }
+
+        byte[] psoDecipherPayload = new byte[mpiLength + 1];
+        psoDecipherPayload[0] = 0x00; // RSA Padding Indicator Byte
+        System.arraycopy(encryptedSessionKeyMpi, 2, psoDecipherPayload, 1, mpiLength);
+        return psoDecipherPayload;
+    }
+
     private byte[] decryptSessionKeyEcdh(byte[] encryptedSessionKeyMpi, ECKeyFormat eckf, CanonicalizedPublicKey publicKey)
             throws IOException {
         int mpiLength = getMpiLength(encryptedSessionKeyMpi);
diff --git a/OpenKeychain/src/test/java/org/sufficientlysecure/keychain/securitytoken/SecurityTokenConnectionCompatTest.java b/OpenKeychain/src/test/java/org/sufficientlysecure/keychain/securitytoken/SecurityTokenConnectionCompatTest.java
index fc368dc00..c5289f32e 100644
--- a/OpenKeychain/src/test/java/org/sufficientlysecure/keychain/securitytoken/SecurityTokenConnectionCompatTest.java
+++ b/OpenKeychain/src/test/java/org/sufficientlysecure/keychain/securitytoken/SecurityTokenConnectionCompatTest.java
@@ -19,7 +19,6 @@ package org.sufficientlysecure.keychain.securitytoken;
 
 
 import java.util.ArrayList;
-import java.util.Arrays;
 import java.util.List;
 
 import org.bouncycastle.util.encoders.Hex;
@@ -28,8 +27,10 @@ import org.junit.Ignore;
 import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.sufficientlysecure.keychain.KeychainTestRunner;
+import org.sufficientlysecure.keychain.securitytoken.operations.PsoDecryptTokenOp;
 
 import static junit.framework.Assert.assertEquals;
+import static org.mockito.Mockito.mock;
 
 
 @RunWith(KeychainTestRunner.class)
@@ -52,7 +53,7 @@ public class SecurityTokenConnectionCompatTest {
     */
 
     @Test
-    public void testPrePostEquals() {
+    public void testPrePostEquals() throws Exception {
         List<String> preApdus = decryptPre_ee8cd38();
         List<String> postApdus = decryptNow();
 
@@ -80,11 +81,9 @@ public class SecurityTokenConnectionCompatTest {
         return apduData;
     }
 
-    public List<String> decryptNow() {
-        int mpiLength = ((((encryptedSessionKey[0] & 0xff) << 8) + (encryptedSessionKey[1] & 0xff)) + 7) / 8;
-        byte[] psoDecipherPayload = new byte[mpiLength + 1];
-        psoDecipherPayload[0] = (byte) 0x00;
-        System.arraycopy(encryptedSessionKey, 2, psoDecipherPayload, 1, mpiLength);
+    public List<String> decryptNow() throws Exception {
+        PsoDecryptTokenOp psoDecryptTokenOp = PsoDecryptTokenOp.create(mock(SecurityTokenConnection.class));
+        byte[] psoDecipherPayload = psoDecryptTokenOp.getRsaOperationPayload(encryptedSessionKey);
 
         CommandApdu command = openPgpCommandApduFactory.createDecipherCommand(psoDecipherPayload);
         List<CommandApdu> chainedApdus = openPgpCommandApduFactory.createChainedApdus(command);