diff --git a/usbSerialForAndroid/src/main/java/com/hoho/android/usbserial/driver/Cp21xxSerialDriver.java b/usbSerialForAndroid/src/main/java/com/hoho/android/usbserial/driver/Cp21xxSerialDriver.java
index c178a67..b95b4b5 100644
--- a/usbSerialForAndroid/src/main/java/com/hoho/android/usbserial/driver/Cp21xxSerialDriver.java
+++ b/usbSerialForAndroid/src/main/java/com/hoho/android/usbserial/driver/Cp21xxSerialDriver.java
@@ -118,7 +118,7 @@ public class Cp21xxSerialDriver implements UsbSerialDriver {
             byte[] buffer = new byte[1];
             int result = mConnection.controlTransfer(REQTYPE_DEVICE_TO_HOST, SILABSER_GET_MDMSTS_REQUEST_CODE, 0,
                     mPortNumber, buffer, buffer.length, USB_WRITE_TIMEOUT_MILLIS);
-            if (result != 1) {
+            if (result != buffer.length) {
                 throw new IOException("Control transfer failed: " + SILABSER_GET_MDMSTS_REQUEST_CODE + " / " + 0 + " -> " + result);
             }
             return buffer[0];
diff --git a/usbSerialForAndroid/src/main/java/com/hoho/android/usbserial/driver/FtdiSerialDriver.java b/usbSerialForAndroid/src/main/java/com/hoho/android/usbserial/driver/FtdiSerialDriver.java
index ee5fcdc..8f5f88f 100644
--- a/usbSerialForAndroid/src/main/java/com/hoho/android/usbserial/driver/FtdiSerialDriver.java
+++ b/usbSerialForAndroid/src/main/java/com/hoho/android/usbserial/driver/FtdiSerialDriver.java
@@ -303,7 +303,7 @@ public class FtdiSerialDriver implements UsbSerialDriver {
             byte[] data = new byte[2];
             int result = mConnection.controlTransfer(REQTYPE_DEVICE_TO_HOST, GET_MODEM_STATUS_REQUEST,
                     0, mPortNumber+1, data, data.length, USB_WRITE_TIMEOUT_MILLIS);
-            if (result != 2) {
+            if (result != data.length) {
                 throw new IOException("Get modem status failed: result=" + result);
             }
             return data[0];
@@ -419,7 +419,7 @@ public class FtdiSerialDriver implements UsbSerialDriver {
             byte[] data = new byte[1];
             int result = mConnection.controlTransfer(REQTYPE_DEVICE_TO_HOST, GET_LATENCY_TIMER_REQUEST,
                     0, mPortNumber+1, data, data.length, USB_WRITE_TIMEOUT_MILLIS);
-            if (result != 1) {
+            if (result != data.length) {
                 throw new IOException("Get latency timer failed: result=" + result);
             }
             return data[0];