diff --git a/eth/downloader/downloader.go b/eth/downloader/downloader.go
index 539aaef40ed..dcda4e521cb 100644
--- a/eth/downloader/downloader.go
+++ b/eth/downloader/downloader.go
@@ -535,9 +535,15 @@ func (d *Downloader) syncToHead() (err error) {
 
 		// If a part of blockchain data has already been written into active store,
 		// disable the ancient style insertion explicitly.
-		if origin >= frozen && frozen != 0 {
+		if origin >= frozen && origin != 0 {
 			d.ancientLimit = 0
-			log.Info("Disabling direct-ancient mode", "origin", origin, "ancient", frozen-1)
+			var ancient string
+			if frozen == 0 {
+				ancient = "null"
+			} else {
+				ancient = fmt.Sprintf("%d", frozen-1)
+			}
+			log.Info("Disabling direct-ancient mode", "origin", origin, "ancient", ancient)
 		} else if d.ancientLimit > 0 {
 			log.Debug("Enabling direct-ancient mode", "ancient", d.ancientLimit)
 		}