diff --git a/cmd/mp4tool/internal/psshdump/psshdump.go b/cmd/mp4tool/internal/psshdump/psshdump.go
index 2d3fba5..368bf0e 100644
--- a/cmd/mp4tool/internal/psshdump/psshdump.go
+++ b/cmd/mp4tool/internal/psshdump/psshdump.go
@@ -43,7 +43,13 @@ func dump(inputFilePath string) error {
 	for i := range bs {
 		pssh := bs[i].Payload.(*mp4.Pssh)
 
-		sysid, _ := pssh.StringifyField("SystemID", "", 0, bs[i].Info.Context)
+		var sysid string
+		for i, v := range pssh.SystemID {
+			sysid += fmt.Sprintf("%02x", v)
+			if i == 3 || i == 5 || i == 7 || i == 9 {
+				sysid += "-"
+			}
+		}
 
 		if _, err := bs[i].Info.SeekToStart(r); err != nil {
 			return err
diff --git a/cmd/mp4tool/internal/psshdump/psshdump_test.go b/cmd/mp4tool/internal/psshdump/psshdump_test.go
index dea7258..2b61a4b 100644
--- a/cmd/mp4tool/internal/psshdump/psshdump_test.go
+++ b/cmd/mp4tool/internal/psshdump/psshdump_test.go
@@ -24,7 +24,7 @@ func TestPsshdump(t *testing.T) {
 				"  size: 52\n" +
 				"  version: 1\n" +
 				"  flags: 0x000000\n" +
-				"  systemId: \n" +
+				"  systemId: 1077efec-c0b2-4d02-ace3-3c1e52e2fb4b\n" +
 				"  dataSize: 0\n" +
 				"  base64: \"AAAANHBzc2gBAAAAEHfv7MCyTQKs4zweUuL7SwAAAAEBI0VniavN7wEjRWeJq83vAAAAAA==\"\n" +
 				"\n",
@@ -37,7 +37,7 @@ func TestPsshdump(t *testing.T) {
 				"  size: 52\n" +
 				"  version: 1\n" +
 				"  flags: 0x000000\n" +
-				"  systemId: \n" +
+				"  systemId: 1077efec-c0b2-4d02-ace3-3c1e52e2fb4b\n" +
 				"  dataSize: 0\n" +
 				"  base64: \"AAAANHBzc2gBAAAAEHfv7MCyTQKs4zweUuL7SwAAAAEBI0VniavN7wEjRWeJq83vAAAAAA==\"\n" +
 				"\n",