diff --git a/fmp/fmp_const.go b/fmp/fmp_const.go
index 82426cd..8c89012 100644
--- a/fmp/fmp_const.go
+++ b/fmp/fmp_const.go
@@ -11,6 +11,7 @@ var (
 	ErrBadHeader          = FmpError("bad header")
 	ErrUnsupportedCharset = FmpError("unsupported character set")
 	ErrBadSectorCount     = FmpError("bad sector count")
+	ErrBadSectorHeader    = FmpError("bad sector header")
 )
 
 const (
diff --git a/fmp/fmp_file.go b/fmp/fmp_file.go
index 1db4053..966c494 100644
--- a/fmp/fmp_file.go
+++ b/fmp/fmp_file.go
@@ -147,6 +147,10 @@ func (ctx *FmpFile) readSector() (*FmpSector, error) {
 		NextID:  parseVarUint64(buf[8 : 8+4]),
 	}
 
+	if ctx.currentSectorID == 0 && sector.PrevID > 0 {
+		return nil, ErrBadSectorHeader
+	}
+
 	payload := make([]byte, sectorPayloadSize)
 	n, err = ctx.stream.Read(payload)