diff --git a/pom.xml b/pom.xml
index da15c52446..37d2b7d668 100644
--- a/pom.xml
+++ b/pom.xml
@@ -19,6 +19,12 @@
 			<artifactId>slf4j-api</artifactId>
 			<version>1.7.12</version>
 		</dependency>
+		<dependency>
+			<groupId>org.apache.commons</groupId>
+			<artifactId>commons-compress</artifactId>
+			<version>1.10</version>
+		</dependency>
+		
 		<dependency>
 			<groupId>org.slf4j</groupId>
 			<artifactId>slf4j-simple</artifactId>
@@ -32,6 +38,18 @@
 			<scope>test</scope>
 		</dependency>
 	</dependencies>
+	<build>
+		<plugins>
+			<plugin>
+				<groupId>org.apache.maven.plugins</groupId>
+				<artifactId>maven-surefire-plugin</artifactId>
+				<version>2.16</version>
+				<configuration>
+					<enableAssertions>true</enableAssertions>
+				</configuration>
+			</plugin>
+		</plugins>
+	</build>
 	<properties>
 		<maven.compiler.source>1.7</maven.compiler.source>
 		<maven.compiler.target>1.7</maven.compiler.target>
diff --git a/src/main/java/net/runelite/cache/fs/DataFile.java b/src/main/java/net/runelite/cache/fs/DataFile.java
index 0ec7d75605..a9b0a7794a 100644
--- a/src/main/java/net/runelite/cache/fs/DataFile.java
+++ b/src/main/java/net/runelite/cache/fs/DataFile.java
@@ -1,16 +1,19 @@
 package net.runelite.cache.fs;
 
+import java.io.ByteArrayOutputStream;
 import java.io.Closeable;
 import java.io.File;
 import java.io.FileNotFoundException;
 import java.io.IOException;
 import java.io.RandomAccessFile;
 import java.nio.ByteBuffer;
+import java.util.Arrays;
 import java.util.Objects;
 import net.runelite.cache.fs.io.InputStream;
 import net.runelite.cache.fs.io.OutputStream;
-import net.runelite.cache.fs.util.BZip2Decompressor;
+import net.runelite.cache.fs.util.BZipDecompressor;
 import net.runelite.cache.fs.util.GZip;
+import org.apache.commons.compress.compressors.gzip.GzipCompressorOutputStream;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -78,7 +81,7 @@ public class DataFile implements Closeable
 	{
 		if (sector <= 0L || dat.length() / 520L < (long) sector)
 		{
-			logger.warn("bad read, dat length {}", dat.length());
+			logger.warn("bad read, dat length {}, requested sector {}", dat.length(), sector);
 			return null;
 		}
 		
@@ -90,6 +93,7 @@ public class DataFile implements Closeable
 		{
 			if (sector == 0)
 			{
+				logger.warn("sector == 0");
 				return null;
 			}
 
@@ -143,11 +147,16 @@ public class DataFile implements Closeable
 
 			if (archiveId != currentArchive || currentPart != part || indexId != currentIndex)
 			{
+				logger.warn("data mismatch {} != {}, {} != {}, {} != {}",
+					archiveId, currentArchive,
+					part, currentPart,
+					indexId, currentIndex);
 				return null;
 			}
 
 			if (nextSector < 0 || dat.length() / SECTOR_SIZE < (long) nextSector)
 			{
+				logger.warn("Invalid next sector");
 				return null;
 			}
 
@@ -164,14 +173,6 @@ public class DataFile implements Closeable
 		return this.decompress(buffer.array());
 	}
 	
-	/**
-	 * 
-	 * @param indexId
-	 * @param archiveId archive to write to
-	 * @param data data to write
-	 * @return the sector the data starts at
-	 * @throws IOException 
-	 */
 	public synchronized DataFileWriteResult write(int indexId, int archiveId, ByteBuffer data, int compression, int revision) throws IOException
 	{
 		int sector;
@@ -312,7 +313,7 @@ public class DataFile implements Closeable
 		return res;
 	}
 	
-	private byte[] compress(byte[] data, int compression, int revision)
+	private byte[] compress(byte[] data, int compression, int revision) throws IOException
 	{
 		OutputStream stream = new OutputStream();
 		stream.writeByte(compression);
@@ -324,10 +325,21 @@ public class DataFile implements Closeable
 				stream.writeInt(data.length);
 				break;
 			case 1:
-				compressedData = (byte[]) null;
-				break;
+				// bzip1?
+				throw new UnsupportedOperationException();
 			default:
-				compressedData = GZip.compress(data);
+				ByteArrayOutputStream bout = new ByteArrayOutputStream();
+				try (GzipCompressorOutputStream out = new GzipCompressorOutputStream(bout))
+				{
+					out.write(data);
+				}
+				compressedData = bout.toByteArray();
+				
+				// check it with the old compressor
+				byte[] data2 = new byte[data.length];
+				GZip.decompress(new InputStream(compressedData), data2);
+				assert Arrays.equals(data, data2);
+				
 				stream.writeInt(compressedData.length);
 				stream.writeInt(data.length);
 		}
diff --git a/src/main/java/net/runelite/cache/fs/Store.java b/src/main/java/net/runelite/cache/fs/Store.java
index 6324d03ad5..0600c8efff 100644
--- a/src/main/java/net/runelite/cache/fs/Store.java
+++ b/src/main/java/net/runelite/cache/fs/Store.java
@@ -101,8 +101,9 @@ public class Store implements Closeable
 		for (Index i : indexes)
 		{
 			int id = i.getIndex().getIndexFileId();
-			//if (id == 3 || id == 7) // XXXXXXXXXXXXX
-				i.load();
+			if (id == 5)
+				break;
+			i.load();
 		}
 	}
 	
diff --git a/src/main/java/net/runelite/cache/fs/util/GZip.java b/src/main/java/net/runelite/cache/fs/util/GZip.java
index 7759c63702..b4111bd957 100644
--- a/src/main/java/net/runelite/cache/fs/util/GZip.java
+++ b/src/main/java/net/runelite/cache/fs/util/GZip.java
@@ -9,24 +9,24 @@ import net.runelite.cache.fs.io.Stream;
 public class GZip {
 	private static final Inflater inflaterInstance = new Inflater(true);
 
-	public static final byte[] compress(byte[] data)
-	{
-		ByteArrayOutputStream compressedBytes = new ByteArrayOutputStream();
-
-		try
-		{
-			GZIPOutputStream e = new GZIPOutputStream(compressedBytes);
-			e.write(data);
-			e.finish();
-			e.close();
-			return compressedBytes.toByteArray();
-		}
-		catch (IOException var3)
-		{
-			var3.printStackTrace();
-			return null;
-		}
-	}
+//	public static final byte[] compress(byte[] data)
+//	{
+//		ByteArrayOutputStream compressedBytes = new ByteArrayOutputStream();
+//
+//		try
+//		{
+//			GZIPOutputStream e = new GZIPOutputStream(compressedBytes);
+//			e.write(data);
+//			e.finish();
+//			e.close();
+//			return compressedBytes.toByteArray();
+//		}
+//		catch (IOException var3)
+//		{
+//			var3.printStackTrace();
+//			return null;
+//		}
+//	}
 
 	public static final void decompress(Stream stream, byte[] data)
 	{
diff --git a/src/test/java/net/runelite/cache/fs/DataFileTest.java b/src/test/java/net/runelite/cache/fs/DataFileTest.java
index 7b99953428..9e47705791 100644
--- a/src/test/java/net/runelite/cache/fs/DataFileTest.java
+++ b/src/test/java/net/runelite/cache/fs/DataFileTest.java
@@ -64,4 +64,18 @@ public class DataFileTest
 			Assert.assertEquals("test", str);
 		}
 	}
+	
+//	@Test
+//	public void testBZip2Compression() throws IOException
+//	{
+//		try (Store store = new Store(folder.getRoot()))
+//		{
+//			DataFile df = new DataFile(store, folder.newFile());
+//			DataFileWriteResult res = df.write(41, 4, ByteBuffer.wrap("test".getBytes()), 1, 0);
+//			DataFileReadResult res2 = df.read(41, 4, res.sector, res.compressedLength);
+//			byte[] buf = res2.data;
+//			String str = new String(buf);
+//			Assert.assertEquals("test", str);
+//		}
+//	}
 }
diff --git a/src/test/java/net/runelite/cache/fs/StoreLoadTest.java b/src/test/java/net/runelite/cache/fs/StoreLoadTest.java
index 98ad26ad86..687a395f6e 100644
--- a/src/test/java/net/runelite/cache/fs/StoreLoadTest.java
+++ b/src/test/java/net/runelite/cache/fs/StoreLoadTest.java
@@ -5,7 +5,7 @@ import org.junit.Test;
 
 public class StoreLoadTest
 {
-	//@Test
+	@Test
 	public void test() throws IOException
 	{
 		Store store = new Store(new java.io.File("d:/rs/07/cache"));//c:/rs/cache"));