TP-Link TL-WR850N v1

The device is a wireless N router with

2 fixed antennas
4 Port 100/10 Switch
1 Port 100/10 Wan Interface
8 MB Flash
64 MB Ram
WPS Button

Note1: The TL-WR840N v4 as well as TL-WR850N v1,v2 & v3 are identical. But TL-WR850N v3 (4/32) can not be supported.

As This two devices are identical to TL-WR840N v4(EU). We can use TL-WR840N v4(EU) Openwrt Firmware without any pain.

→ Install OpenWrt (generic explanation)

To burn the OpenWrt firmware in to the TL-WR850n v1 & v2, you will need to setup a TFTP server in a local machine.There are several different TFTP server options to download and run, all you need to do is find the one that better suits you. The TFTP server, after installed, need to be configured to work on IP 192.168.0.66 (port 69). Insert the firmware file inside the TFTP server folder and follow the instructions below:

Run the TFTP server and add the firmware file in the folder. Rename the firmware file to tp_recovery.bin (otherwise the router won't find it).
Connect the router (while it's turned off) by one of the LAN ports to the machine running the TFTP server.
Press and hold the reset button while turning on the router. The router will search for the TFTP server and download any tp_recovery.bin file that it finds out. While the file is being transferred, the router's LEDs will start to blink.
If the download is successfully done, the router will automatically burn the new firmware and restart itself.

/proc # cat mtd
dev:    size   erasesize  name
mtd0: 00020000 00010000 "boot"
mtd1: 00140000 00010000 "kernel"
mtd2: 00660000 00010000 "rootfs"
mtd3: 00010000 00010000 "config"
mtd4: 00010000 00010000 "romfile"
mtd5: 00010000 00010000 "rom"
mtd6: 00010000 00010000 "radio"

Note2: OEM firmware is not available for TL-WR850N v1. Since the device is identical to TL-WR850N v2. We can use v2 OEM firmware using following process

Restoring the router to its official Firmware you'll have to modify the file from TP-Link in order to remove the 512 byte header. Follow the instructions:

Go to TP-Link official site and download the firmware file you want.
After downloaded the file, use the command
```
dd if="TL-WR850Nv2_example_official_firmware_file.bin" of="tlwr850nv2_file_with_removed_header.bin" bs=512 skip=1
```
The second name here can be whatever you want, since it's just a name for the resulting file generated by the command.
Now that you have the valid firmware file, rename it to tp_recovery.bin and place it in the TFTP server folder to burn it on the device.

Versions	v1	v2
Instruction Set	MIPS 24Kc
Vendor	MediaTek
System-On-Chip	MT7628NN 1850-AJCJL EAP1J400	MT7628NN 1706-AJCSL EAP0W363
CPU Frequency	580MHz
BogoMIPs	386.04
Flash-Chip	GigaDevice GD25Q64CSIG
Flash Size	8MB
RAM-Chip	ESMT M14D5121632A-2.5B
RAM-Size	64MB
Wlan Hardware	MediaTek MT7628N
Switch	MT7628N built-in
Serial	Yes
JTAG	Yes