diff --git a/eth/downloader/downloader.go b/eth/downloader/downloader.go
index 09837a3045..dc4fb425a6 100644
--- a/eth/downloader/downloader.go
+++ b/eth/downloader/downloader.go
@@ -485,6 +485,12 @@ func (d *Downloader) syncToHead() (err error) {
 	if mode == ethconfig.SnapSync {
 		if height <= uint64(fsMinFullBlocks) {
 			origin = 0
+			// For genesis block, switch to full sync
+			if height == 0 {
+				mode = ethconfig.FullSync
+				d.mode.Store(uint32(mode))
+				log.Info("Switching to full sync for genesis block")
+			}
 		} else {
 			pivotNumber := pivot.Number.Uint64()
 			if pivotNumber <= origin {
diff --git a/eth/handler.go b/eth/handler.go
index aaea00e037..a4636e52a9 100644
--- a/eth/handler.go
+++ b/eth/handler.go
@@ -177,7 +177,11 @@ func newHandler(config *handlerConfig) (*handler, error) {
 		}
 	} else {
 		head := h.chain.CurrentBlock()
-		if head.Number.Uint64() > 0 && h.chain.HasState(head.Root) {
+		if head.Number.Uint64() == 0 {
+			// For genesis block, always use full sync
+			h.snapSync.Store(false)
+			log.Info("Using full sync for genesis block")
+		} else if head.Number.Uint64() > 0 && h.chain.HasState(head.Root) {
 			// Print warning log if database is not empty to run snap sync.
 			log.Warn("Switch sync mode from snap sync to full sync", "reason", "snap sync complete")
 		} else {