TP-Link ER605 v2 OpenWRT Installation Guide

This guide outlines the steps to install OpenWRT on the TP-Link ER605 v2 router. OpenWRT provides a customizable, open-source router firmware that offers improved functionality and flexibility.

Prerequisites

Before starting, ensure you have the following:

• TP-Link ER605 v2 Router: This guide is specifically for the v2 model.
• OpenWRT Firmware: Download the appropriate firmware for the TP-Link ER605 v2 from the official OpenWRT website by searching 'ER605'.
• Backup of your current router configuration (optional but recommended).
• Hardware:
  • USB-to-serial adapter (if you need to use serial recovery mode).
  • Ethernet Cable: For a wired connection between your router and PC.

Steps to Install

1) Enable SSH Access

1. Log into the ER605 Web Interface: Open a browser and navigate to http://192.168.0.1.

2. Navigate to Remote Assistance:

   • Go to System Tools > Diagnostics > Remote Assistance.
   • Enable Remote Assistance.

3. Generate SSH Root Password:

   • Generate your SSH password by clicking the provided link for password generation.

4. SSH into ER605:

   • Open a terminal and connect to the router via SSH:

     ssh -o hostkeyalgorithms=ssh-rsa -l root <ip_address>

   • If SSH client 'no matching host key or key exchange method' use:

     ssh -o hostkeyalgorithms=ssh-rsa -o KexAlgorithms=+diffie-hellman-group1-sha1 -l root <ip_address>

   • If using version 2.0.1 or below, login using the username root and the generated password.

   • For version 2.1.1 and above, log in using your web configuration credentials and run the following commands:

     enable
     debug

     When prompted for a password, use the "CLI debug mode password" generated earlier.

2) Download the Files

1. Backup MTD Partitions (Recommended):

   • Backup your MTD partitions. For more details, follow this guide: OpenWRT Backup Guide.

   • Use backup_mtd.sh and copy the backups to an external flash drive or TFTP.

2. Download the Necessary Files:

   • SSH into the router and execute the following commands to download the required files:

     cd /tmp
     curl -o er605v2_write_initramfs.sh https://raw.githubusercontent.com/safesploitOrg/openwrt-install-er605v2/main/er605v2_write_initramfs.sh
     curl -o openwrt-23.05.5-ramips-mt7621-tplink_er605-v2-initramfs-kernel.bin https://downloads.openwrt.org/releases/23.05.5/targets/ramips/mt7621/openwrt-23.05.5-ramips-mt7621-tplink_er605-v2-initramfs-kernel.bin
     chmod +x er605v2_write_initramfs.sh

3) Install the Firmware

1. Run the Installation Script:

   • Execute the following command to flash the initramfs image to your ER605:

     ./er605v2_write_initramfs.sh openwrt-initramfs-compact.bin

2. Reboot the ER605:

   • After the flashing process completes, reboot the ER605 router.

3. Access the Web Interface:

   • Open a web browser and go to http://192.168.1.1/. If the page does not load, wait a bit longer or clear your browser cache. Ensure there are no other routers or DHCP servers on the same network to avoid IP conflicts.

4. Follow the Setup Instructions:

   • After successfully accessing the web interface, follow the on-screen instructions to complete the setup.

5. Upgrade to Latest OpenWRT Version:

   • Download the latest sysupgrade image from OpenWRT Downloads.
   • Use the web interface to upload and upgrade to the latest stable release.

4) Reboot and Enjoy OpenWRT!

Once the upgrade is complete, your ER605 should be running OpenWRT. Enjoy the enhanced features and flexibility!

Post-Installation

1. Configure OpenWRT:

   • Set up your Wi-Fi networks, firewall, and routing preferences.
   • Change your root password for security.

2. Harden SSH For enhanced security, disable password authentication for SSH and configure SSH keys.

   1. Disable Password Authentication: Edit the /etc/config/dropbear file and set PasswordAuth to off.

   2. Restart the Dropbear service:

      /etc/init.d/dropbear restart

3. Restore Backup (if applicable):

   • If you made a backup of your MTD partitions, you can restore them at this point.

Troubleshooting

• Router not booting: If the router fails to boot into OpenWRT, you may need to perform a serial recovery using a USB-to-serial adapter and the proper recovery commands.
• Can't access web interface: Try disconnecting all unnecessary devices from the router to avoid IP conflicts.
• Firmware Mismatch: Ensure that the firmware file is correct for the ER605v2 version you have.

Credits

• This guide is based on community contributions and research from various OpenWRT forums.
• Special thanks to chill1Penguin for the original setup and guidance on flashing the TP-Link ER605v2 with OpenWRT.