diff --git a/.gitignore b/.gitignore
index 7300ac44..f266b7fa 100644
--- a/.gitignore
+++ b/.gitignore
@@ -5,7 +5,7 @@
 *.apk
 *.ap_
 
-# Files for the Dalvik VM
+# Files for the ART/Dalvik VM
 *.dex
 
 # Java class files
@@ -14,6 +14,7 @@
 # Generated files
 bin/
 gen/
+out/
 
 # Gradle files
 .gradle/
@@ -31,23 +32,33 @@ proguard/
 # Android Studio Navigation editor temp files
 .navigation/
 
-### Android Patch ###
-gen-external-apklibs
+# Android Studio captures folder
+captures/
 
+# Intellij
+*.iml
+.idea/workspace.xml
+.idea/tasks.xml
+.idea/gradle.xml
+.idea/dictionaries
+.idea/libraries
 
-### Java ###
-*.class
+# Keystore files
+*.jks
 
-# Mobile Tools for Java (J2ME)
-.mtj.tmp/
+# External native build folder generated in Android Studio 2.2 and later
+.externalNativeBuild
 
-# Package Files #
-*.jar
-*.war
-*.ear
+# Google Services (e.g. APIs or Firebase)
+google-services.json
 
-# virtual machine crash logs, see http://www.java.com/en/download/help/error_hotspot.xml
-hs_err_pid*
+# Freeline
+freeline.py
+freeline/
+freeline_project_description.json
+
+### Android Patch ###
+gen-external-apklibs
 
 
 ### Intellij ###
diff --git a/libaums/CMakeLists.txt b/libaums/CMakeLists.txt
new file mode 100644
index 00000000..577e727e
--- /dev/null
+++ b/libaums/CMakeLists.txt
@@ -0,0 +1,9 @@
+cmake_minimum_required(VERSION 3.4.1)
+
+add_library( errno-lib
+
+             # Sets the library as a shared library.
+             SHARED
+
+             # Provides a relative path to your source file(s).
+             src/c/errno.c )
\ No newline at end of file
diff --git a/libaums/build.gradle b/libaums/build.gradle
index 6950aa27..9bff7d27 100644
--- a/libaums/build.gradle
+++ b/libaums/build.gradle
@@ -31,6 +31,12 @@ android {
     lintOptions {
         abortOnError false
     }
+
+    externalNativeBuild {
+        cmake {
+            path "CMakeLists.txt"
+        }
+    }
 }
 
 dependencies {
diff --git a/libaums/src/c/errno.c b/libaums/src/c/errno.c
new file mode 100644
index 00000000..382e6d1d
--- /dev/null
+++ b/libaums/src/c/errno.c
@@ -0,0 +1,14 @@
+#include <errno.h>
+#include <string.h>
+#include <jni.h>
+
+JNIEXPORT jint JNICALL
+Java_com_github_mjdev_libaums_ErrNo_getErrno(JNIEnv *env, jobject thiz) {
+    return errno;
+}
+
+JNIEXPORT jstring JNICALL
+        Java_com_github_mjdev_libaums_ErrNo_getErrstr(JNIEnv *env, jobject thiz) {
+    char *error = strerror(errno);
+    return (*env)->NewStringUTF(env, error);
+}
\ No newline at end of file
diff --git a/libaums/src/main/java/com/github/mjdev/libaums/ErrNo.java b/libaums/src/main/java/com/github/mjdev/libaums/ErrNo.java
new file mode 100644
index 00000000..3799a2db
--- /dev/null
+++ b/libaums/src/main/java/com/github/mjdev/libaums/ErrNo.java
@@ -0,0 +1,14 @@
+package com.github.mjdev.libaums;
+
+/**
+ * Created by magnusja on 5/19/17.
+ */
+
+public class ErrNo {
+    static {
+        System.loadLibrary("errno-lib");
+    }
+
+    public static native int getErrno();
+    public static native String getErrstr();
+}
diff --git a/libaums/src/main/java/com/github/mjdev/libaums/usb/JellyBeanMr2Communication.java b/libaums/src/main/java/com/github/mjdev/libaums/usb/JellyBeanMr2Communication.java
index 30c42811..bb481fc2 100644
--- a/libaums/src/main/java/com/github/mjdev/libaums/usb/JellyBeanMr2Communication.java
+++ b/libaums/src/main/java/com/github/mjdev/libaums/usb/JellyBeanMr2Communication.java
@@ -8,6 +8,9 @@
 import android.hardware.usb.UsbDeviceConnection;
 import android.hardware.usb.UsbEndpoint;
 import android.os.Build;
+import android.system.ErrnoException;
+
+import com.github.mjdev.libaums.ErrNo;
 
 import java.io.IOException;
 import java.nio.ByteBuffer;
@@ -39,7 +42,7 @@ public int bulkOutTransfer(ByteBuffer src) throws IOException {
                 src.array(), src.position(), src.remaining(), TRANSFER_TIMEOUT);
 
         if (result == -1) {
-            throw new IOException("Could not write to device, result == -1");
+            throw new IOException("Could not write to device, result == -1 errno " + ErrNo.getErrno());
         }
 
         src.position(src.position() + result);
@@ -52,7 +55,7 @@ public int bulkInTransfer(ByteBuffer dest) throws IOException {
                 dest.array(), dest.position(), dest.remaining(), TRANSFER_TIMEOUT);
 
         if (result == -1) {
-            throw new IOException("Could not read from device, result == -1");
+            throw new IOException("Could not read from device, result == -1 errno " + ErrNo.getErrno() + " " + ErrNo.getErrstr());
         }
 
         dest.position(dest.position() + result);