Netgear R6250 Router Flash Merlin Firmware.
I buy a R6250 Router with the Merlin Firmware. But when I link it by 192.168.1.1 with default username: admin, password: password, �the webpage show it's the official firmware, not �Merlin. Thanks to the Customer Services's direct, I record the process here.

Official Firmware: 高级->管理->路由器升级->浏览->选择 tomato-R6250-initial.chk ->上传, 升级.
Tomato Firmware: Administration->Upgrade->Select 20161218-R6250_7.1.trx->Upgrade.
Merlin Firmware: Skip Guide->username: admin, password: admin->系统管理->固件升级->选择文件 R6300V2_380.65-X7.4.trx->上传, 升级.

系统管理->系统设置->Enable JFFS custom scripts and configs->是->应用本页面设置. Software Center->未安装->shadowsocks->Config like this: