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 72b2a1fb2..99b1f95ac 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
@@ -168,7 +168,7 @@ public class CcidTransceiver {
 
         int sentBytes = 0;
         while (sentBytes < data.length) {
-            int bytesToSend = Math.min(usbBulkIn.getMaxPacketSize(), data.length - sentBytes);
+            int bytesToSend = Math.min(usbBulkOut.getMaxPacketSize(), data.length - sentBytes);
             sendRaw(data, sentBytes, bytesToSend);
             sentBytes += bytesToSend;
         }