diff --git a/common/block.go b/common/block.go
index dec1fe1..9489a07 100644
--- a/common/block.go
+++ b/common/block.go
@@ -137,7 +137,12 @@ func NewDecodedBlock(data []byte, colors *Colors) (db *DecodedBlock, err error)
 		return
 	}
 
-	offset += buf.Pos + 4
+	// There is a bug before Go 1.7 that enforces
+	// to add 4 as an offset after the compressed
+	// geometry data. This is resolved via build tags
+	// and definitions in pre17offset.go and
+	// post17offset.go.
+	offset += buf.Pos + afterCompressOfs
 	buf.Pos = 0
 	if offset >= dataLen {
 		return nil, ErrBlockTruncated
diff --git a/common/post17offset.go b/common/post17offset.go
new file mode 100644
index 0000000..6d9691c
--- /dev/null
+++ b/common/post17offset.go
@@ -0,0 +1,10 @@
+// Copyright 2016 by Sascha L. Teichmann
+// Use of this source code is governed by the MIT license
+// that can be found in the LICENSE file.
+
+// +build go1.7
+
+package common
+
+// afterCompressOfs is not necessary after Go 1.7.
+const afterCompressOfs = 0
diff --git a/common/pre17offset.go b/common/pre17offset.go
new file mode 100644
index 0000000..b7d9a30
--- /dev/null
+++ b/common/pre17offset.go
@@ -0,0 +1,10 @@
+// Copyright 2016 by Sascha L. Teichmann
+// Use of this source code is governed by the MIT license
+// that can be found in the LICENSE file.
+
+// +build !go1.7
+
+package common
+
+// afterCompressOfs is necessary before Go 1.7.
+const afterCompressOfs = 4