The TP-Link TL-MR3420 is a Fast Ethernet b/g/n 300M (two 3 dBi omni-antennas) wireless router with USB 2.0.
The TP-Link TL-MR3220 is a Fast Ethernet b/g/n Lite-N 150M (one 5 dBi omni-antennae) wireless router with USB 2.0.
| CPU | Ram | Flash | Network | USB | Serial | JTag |
| Atheros AR7241@400MHz | 32MiB | 4MiB | 4 x 100 | 2.0 | Yes | No |
TL-MR3420: Atheros AR9287 wireless chip. Single-band, 2x2 MIMO configuration
TL-MR3220: Atheros AR9285 wireless chip. Single-stream (no MIMO, Lite-N)
This section details what is required to install and upgrade OpenWrt. First we link to software that you should download before you start reading the instructions on how to install.
Please double-check if the image revision you are downloading is newer than supported by the "Model Version" of your router.
-
Download latest original firmware for your router
MR3420/
MR3220 just in case upgrade goes wrong and need it to recover Internet access.
This section deals with how you install OpenWrt from a device freshly opened. Plus the steps required such as reset to factory defaults if the device has already been configured
Note: Reset router to factory defaults if it has been previously configured.
Note: Newer TP-Link retail firmwares (confirmed on v2.4 devices, but definitely not on v2.0) include a crude mechanism to prevent you uploading unsuitable firmware. It does this by checking the filename, so you may need to rename the *-factory.bin file to the name of a TP-Link retail firmware file. e.g. wr741nv1_en_3_12_4_up(100910).bin
-
Login with user name: admin password: admin
Use left navigation panel and go to System Tools
Navigate to
- Factory Defaults and click on
Restore if it has been previously configured.
Then navigate to - Firmware Upgrade
Upload previously chosen -factory.bin file to router
Click on Upgrade button and wait for it to reboot
Do NOT turn off the power during upgrade
Wait about 120 seconds to start up, see SYS LED activity.
Don't clear your browser cache! Please report
here what you installed, if do
http://192.168.1.1/ work anyway and which
link let you get in. Successful ones have
removed. This only happen once, so your input is important.
Clear your browser cache if you are sure some web interface is installed, but can't access to
http://192.168.1.1/Set a root password
Once password has been setup Telnet is no longer available, use
SSH instead to connect.
Install the OpenWrt image using "Firmware Upgrade" from the orginal firmware.
Download openwrt-ar71xx-generic-tl-mr3420-v1-squashfs-factory.bin
Connect your pc via serial interface.
use a tftpd server name the the firmware code.bin and set your ip to 192.168.1.27
power on the router, and type tpl if "Autoboot in .." occurs (type fast!)
if it works you now should see:
ar7100>
ar7100> erase 0x9f020000 +0x3c0000
ar7100> tftpboot 0x81000000 code.bin
ar7100> cp.b 0x81000000 0x9f020000 0x3c0000
ar7100> bootm 0x9f020000
source: http://eko.one.pl/?p=openwrt-mr3420
| Model | MR3420 | MR3220 |
| Version | 1 | 1.1 | 1.2 | 1 | 1.2 |
| Architecture: | MIPS 4KEc V6.4 |
| Manufacturer: | Atheros |
| Bootloader: | U-Boot |
| System-On-Chip: | Atheros AR7241@400MHz |
| Flash chip: | MACRONIX MX25L3206E | cFeon F32-100HIP | Winbond W25Q32BV | Spansion FL032PIF | cFeon F32-100HIP |
| Flash size: | 4 MiB |
| RAM chip: | Zentel A3S56D40FTP -G5 |  | Zentel A3S56D40FTP -G5 |
| RAM size: | 32 MiB |
| Wireless | Atheros AR9287 | Atheros AR9285 |
| Antenae(s) | 2 Removables x 3 dBi | 1 Removable x 5 dBi |
| Ethernet: | AG71xx 4 LAN, 1 WAN 10/100 |
| USB: | 1 x 2.0 |
| Serial: | Unfriendly |
| JTAG: | No |
Pin 1 is clearly marked on the board.
To get the serial connection work reliably, you have to connect a 10k pullup resistor between the TX and the 3.3V pin. This is because the TX pin is connected to a voltage divider (2x5.6k) and a capacitor is put between the real pin and the TX connector. 5)
Now connect a serial hack adapter (DKU-5, CA-42) and away you go!
The right settings for accessing the serial console are as follows:
Bits per second: 115200
Data bits: 8
Stop bits: 1
Parity: None
Flow control: None
Password to get into uboot prompt is tpl
Password to get root login is 5up
Since this part is identical for all devices, see Basic configuration.
Note: (TP-Link MR4320 v1.2) In case the vlan switch configuration is not created automagically (⇐ 10.03.1) and there is eth0 and eth1 after bootup change /etc/config/network to reflect the vlan setup by adding the lines below. Also replace the 'option ifname "ethX"' accordingly (eth0.1, eth0.2). The proper ethernet port layout has still to be confimed.
config switch eth0
option reset 1
option enable_vlan 1
config switch_vlan
option device eth0
option vlan 1
option ports "0t 1 2 3 4"
config switch_vlan
option device eth0
option vlan 2
option ports "0t 5"
In MR3220 v1.2 is:
config 'switch'
option 'name' 'eth0'
option 'reset' '1'
option 'enable_vlan' '1'
config 'switch_vlan'
option 'device' 'eth0'
option 'vlan' '1'
option 'ports' '0 1 2 3 4'
Failsafe is a quite popular feature, of this router, thats lets you recover instantly from a misconfiguration above.
Use the QSS button instead of reset button, everything else is identical to generic failsafe document.
Failsafe may not work in Backfire before r29661, so it's confirmed to not work at Backfire 10.03.1 launch (r29592). Be extremely cautious on what you're doing or go directly to serial recovery.
Back to top
toh/tp-link/tl-mr3420.txt · Last modified: 2012/02/19 04:00 by nilfred
Trunk r24439 
