cmd/utils: support use NetworkId to distinguish chapel when do syncing (

#2573)

README.md

@@ -149,8 +149,6 @@ unzip testnet.zip
 #### 3. Download snapshot
 Download latest chaindata snapshot from [here](https://github.com/bnb-chain/bsc-snapshots). Follow the guide to structure your files.
 
-Note: If you encounter difficulties downloading the chaindata snapshot and prefer to synchronize from the genesis block on the Chapel testnet, remember to include the additional flag `--chapel` when initially launching Geth.
-
 #### 4. Start a full node
 ```shell
 ./geth --config ./config.toml --datadir ./node  --cache 8000 --rpc.allow-unprotected-txs --history.transactions 0

cmd/geth/main.go

@@ -334,9 +334,6 @@ func prepare(ctx *cli.Context) {
   5. Networking is disabled; there is no listen-address, the maximum number of peers is set
      to 0, and discovery is disabled.
 `)
-
-	case !ctx.IsSet(utils.NetworkIdFlag.Name):
-		log.Info("Starting Geth on BSC mainnet...")
 	}
 	// If we're a full node on mainnet without --cache specified, bump default cache allowance
 	if !ctx.IsSet(utils.CacheFlag.Name) && !ctx.IsSet(utils.NetworkIdFlag.Name) {

cmd/utils/flags.go

@@ -2073,7 +2073,7 @@ func SetEthConfig(ctx *cli.Context, stack *node.Node, cfg *ethconfig.Config) {
 		}
 		cfg.Genesis = core.DefaultBSCGenesisBlock()
 		SetDNSDiscoveryDefaults(cfg, params.BSCGenesisHash)
-	case ctx.Bool(ChapelFlag.Name):
+	case ctx.Bool(ChapelFlag.Name) || cfg.NetworkId == 97:
 		if !ctx.IsSet(NetworkIdFlag.Name) {
 			cfg.NetworkId = 97
 		}