It finally happened… After experimenting with alternative firmware for my WNR3500L router, I uploaded the wrong version and converted the device into a rather expensive paperweight. After some searching, I found this page, explaining how to revitalize the router by using a USB-TTL converter cable. You can get (e.g. CP2102 Module Modul USB to TTL Converter) for a few bucks Ebay, but expect a few weeks for the delivery from China. If you follow the tutorial on the OpenRouters page closely, it should work out quite nicely.
It happened again. I flashed an unsupported version of LEDE on the device and it did not want to boot again. I followed the same procedure as described here, but the router was complaining about a version missmatch of the device ID and the image ID. Turns out, I had to explicitly use binary mode for FTP. Here are the steps again.
- Connect the serial cables as shown
- Make sure router is off
- Launch minicom in a terminal and make sure the settings are valid for ttyUSB0
- Boot the router and immediately press Ctrl+C in the terminal
- Type tftpd in the prompt, the router should start a FTP server on 192.168.1.1
- Open a second terminal, cd into the directory where the firmware is
- Make sure its the right version 🙂
- Start the FTP client: ftp 192.168.1.1
- Change to binary mode (this is very important): mode binary
- Move the file: put FIRMWARE.chr
- The router should detect the file and process it
- Reboot and enjoy
Connecting a Serial TTYUSB Device to the Router
When you see this message below, you need to abort the boot process.
Willkommen zu minicom 2.7 Optionen: I18n Übersetzt am Feb 7 2016, 13:37:27. Port /dev/ttyUSB0, 17:47:29 Drücken Sie CTRL-A Z für Hilfe zu speziellen Tasten Found a Samsung NAND flash with 2048B pages or 128KB blocks; total size 128MB Decompressing...done CFE for WNR3500Lv2 version: v1.0.9 Build Date: Fri May 6 11:54:17 CST 2011 Init Arena Init Devs. Boot partition size = 262144(0x40000) NFLASH Boot partition size = 524288(0x80000) et0: Broadcom BCM47XX 10/100/1000 Mbps Ethernet Controller 5.60.136 CPU type 0x19749: 480MHz Tot mem: 131072 KBytes Device eth0: hwaddr 84-1B-5E-4E-FF-84, ipaddr 192.168.1.1, mask 255.255.255.0 gateway not set, nameserver not set Checking crc...done. Loader:raw Filesys:raw Dev:flash0.os File: Options:(null) Loading: .. 3848 bytes read Entry at 0x80001000 Closing network. Starting program at 0x80001000
When pressing Ctrl+C does not work, make sure your minicom settings look like this:
A - Serieller Anschluss : /dev/ttyUSB0 | B - Pfad zur Lockdatei : /var/lock | C - Programm zur Rufannahme : | D - Programm zum Wählen : | E - Bps/Par/Bits : 115200 8N1 | F - Hardware Flow Control : Nein | G - Software Flow Control : Nein