diff --git a/fmp/fmp_chunk.go b/fmp/fmp_chunk.go
index a0babd0..4d1842b 100644
--- a/fmp/fmp_chunk.go
+++ b/fmp/fmp_chunk.go
@@ -1,7 +1,5 @@
 package fmp
 
-import "fmt"
-
 func (ctx *FmpFile) readChunk(payload []byte) (*FmpChunk, error) {
 
 	// Simple data
@@ -228,5 +226,5 @@ func (ctx *FmpFile) readChunk(payload []byte) (*FmpChunk, error) {
 		}, nil
 	}
 
-	return nil, fmt.Errorf("unknown chunk type 0x%02X", payload[0])
+	return nil, ErrBadChunk
 }
diff --git a/fmp/fmp_const.go b/fmp/fmp_const.go
index 8c89012..f5d4551 100644
--- a/fmp/fmp_const.go
+++ b/fmp/fmp_const.go
@@ -12,6 +12,7 @@ var (
 	ErrUnsupportedCharset = FmpError("unsupported character set")
 	ErrBadSectorCount     = FmpError("bad sector count")
 	ErrBadSectorHeader    = FmpError("bad sector header")
+	ErrBadChunk           = FmpError("bad chunk")
 )
 
 const (