Tp-link tl-wdr7400 V4.0 8MB 64MB need help identifying board

Installing and Using OpenWrt
1

hi,
I have just recently ordered a TP-LINK TL-WDR7400 for 50$ and I am wondering what I will be getting and if I will be able to install openwrt?

there seems to be a AC1750 and a AC2100 version, see links below.

TP-Link TL-WDR7400
Qualcomm Atheros QCA9561
ROM：8 MB
RAM：64 MB
Qualcomm Atheros QCA9561 + QCA9880
1750 Mbps
Qualcomm Atheros QCA9561
1000 Mbps

TP-Link TL-WDR7400 AC1750 (450Mbps & 1300Mbps) Version 3x3 MIMO
TP-Link TL-WDR7400 AC2100 (1733Mbps & 300Mbps) MU-MIMO

I would like to run mosquitto, ABP and squid on it.

I would like to get information on the follwing subjects:
get USB working
get UART bootloader access
install a mPCIe expansion / riser card
install mPCIe SATA, USB3.0 & SD SDHC SDXC to Mini PCIe Memory Card expansion board to give squid some room to play with.
NAS
4G / LTE via USB dongle
RAM / ROM chip upgrade

Is there some information on that probably even for the TP-Link TL-WDR7500 or Archer C7?

2

Good luck with that under any firmware, as you're likely to exhaust the memory.

From https://openwrt.org/supported_devices/432_warning

64 MB may still have issues with stability, depending on your hardware and use cases

Right now, I don't see it as being supported. https://openwrt.org/toh/start?dataflt[Model*~]=WDR7400

https://openwrt.org/toh/tp-link/tp-link_tl-wdr7400_v2 is pretty empty and hasn't been edited since December, 2016.

For links to introductory information on porting a "new" device, see Huawei HG255S Add Support - #5 by tmomas

Unless an existing dev has one that they personally consider a treasure, there's unlikely to be a lot of excitement in porting to an under-resourced device.

I'd recommend another unit for your application, one with at least 128 MB or 256 MB RAM and a multi-core ARM processor, if not an x86. By the time you get done "upgrading" that unit (which has the additional challenges of apparently being Chinese market only), you could have bought a top-end, ARM-based all-in-one unit and had it delivered, up, and running months prior (if at all possible).

1 Like
3

thank you for your concerns and links jeff.
I just started to look around a bit. there is admittingly faster solutions. I like my little projects, even though when they seem to be not making much sense.

I will do some research with the wdr7400 and then look into an arm7 router board like you had recommended. the pcie cards ( Broadcom BCM943460MC) seem to go up to 867Mb, or is there more?
arm should have a much lower power demand than x86?

could the arm7 also run openhab, and pfsense, router distro on a VM? or will that be tricky on arm?

4

Some things you should be aware of, past the challenges of bringing what might be a completely undocumented device onto new firmware:

  • Most PCIe / M.2 cards are intended for single-band, client-only operation
  • Broadcom wireless chips, with some notable exceptions, have limited to no support in open-source drivers
  • There are several 64-bit x86/arm64 platforms that idle at 10 W or below for the entire system
  • You can't beat physics, more capable, faster hardware with greater load will consume more power
  • Consumer-grade, all-in-one routers are already stressed for processing power and memory at today's rates
  • Consumer-grade, all-in-one routers aren't general-purpose computing platforms
  • pfSense runs on top of FreeBSD and your chances of getting that to run on a random consumer-grade all-in-one router platform is about zero, even if it is ARM (to be clear, FreeBSD is my preferred OS)
  • Many consider it a significant security flaw to be running anything but routing and firewall on your perimeter router

So, given all that, my recommendations would be:

  • Buy a well-supported ARM or x86 device to use as a router/firewall
  • Buy a managed switch (full VLAN support)
  • Buy a couple APs, or used all-in-one routers that are already well-supported by OpenWrt
  • Buy what you need to run your services off the router, be it a Raspberry Pi-class device or an energy efficient x86/amd64 box and run your services in containers, jails, whatever your OS of choice supports
1 Like
5

Hi, I am back. thanks for all your help and advice.
I just received my TL-WDR7400 V4.0 with 8MB and 32MB
XMD QH64AHIG
Zentel A3R12E40DBF
HST-2027DAR 10/100 BASE-TX
HST-1025DAR 10/100 BASE-TX

TL-WDR7400_V4
TL-WDR7400_V4.jpg1343×989 376 KB

who can identify this?

6

Well first step should be to enable UART serial and see how it works and whether you are able to stop the boot or not.

But most importantly it has 32mb RAM which may only be workable in v17 and even if you can work it out in v18 the max you can get is a working AP and that's about it.

If you really wanna make this unit work, then upgrade the ram to at least 64mb for an entry level device for simple routing needs and to 128mb for anything more than that.

7

undertood, thank you.

I have to correct myself. It seems to be 64MB, not 32MB.

I had in mind to upgrade flash from 8MB to 16MB / 32MB or even 64MB or so. That is a 10 minute swap.
Can someone tell me what DIP8 should work?
If I program the chip before soldering then the boot loader shouldn't matter too much, or does it?
I am not a specialist in this.

the 64MB A3R12E40DBF seems to be 84-ball FBGA(μBGA) (FBGA84).
which 128MB / 256MB / 512MB chip should work OK?

8

I don't see the point of this model. What good is 4x4 ac wifi, when the Ethernet ports aren't gigabit? Also there's no USB port which is a limitation on what can be done with it even in a low-speed context.

First try to get OpenWrt to run on it stock before thinking of modifications.

SPI NOR flash larger than 16 MB requires a different driver.

9

I fully understand that100 Mb ethernet ports and and non-existing USB2.0 don't go well with AC wireless.
I have in mind to distribute wireless signal in the house and connect the 2 floors via network cable, connected to gigabit routers.
run a MDADM raid 1+0 / raid 5 / raid 6 on the router an check the processor load (USB 3.0).
I would loose half the bandwidth if I do it wirelessly for the link between the floors.
everything that I can connect per lan cable won't go missing from the wireless bandwidth.

No problem re-soldering the DIP but I have never reballed. I thought I would rather brick 50$ than double and more than that.
It is a test object.

1024Mb FBGA84 cost nothing

or 2048Mb for 5x the price of the "little brother"

25Q512 for 0.50 US$ a piece

will the above 64MB model work, will it accept any SPI NOR or is there a model / make to be prefered? how difficult is it to implement the other driver?

10

mk24 thank you, I was just looking into it what made me actually buy this router.
I was asking myself why I did buy a router without 1Gb lan and looked at the advert again.
It says: Wired Transfer Rate: 10/100/1000Mbps

I am just trying to get my money back from the seller, thank you!
Not worth much that router, you are absolutely right

I will test now if I can load openwrt onto it and share my results.

any thoughts regarding the chips / sizes?

11

TL-WDR7400_V4_JTAG

I just tapped into it via JTAG and get the "data" below. How can I proceed from there, I tried also TFTP with IP 192.168.0.66 and 192.168.1.66 but don't get any response.
I might just be doing something wrong though?

ÿÓxµÇÿÇåÇåǵ°µ°f×■f×å×~×■fµÿxÿ x ÿÿÇåÇåÇf~fµf×■×~µfµÿx ÿÓ ÿÿÇåÇåÇf~fµf×å×~×■fµÿxÿ ÿx ÿÿÇåÇåǵÓå× ~■f~å×µ×fµ×f~ÿ ÿµÿÿÇåÇåÇ~µ×■fÿå×fxå~×ÿ ÿµÿÿÇåÇåÇfåxfµf°~ffxf×°×~µf~å×µ×få~ ÿÿÇ~µ°µ°µf°~ffxµf~Ó×å×å×x ÿ×µ×f~Ó×f ÿÿå×å×ÿ~å×× ÿÿµÿfÿ` ``ff×ÿåÿ°ÿ×ÿ■fÿÇÿÿÇ~µ°µ°µf°~ffxµf~Ó×å×å×xµffå°µ°fx

12

Make sure that your connections (ground in particular) are good and try the common bitrates (115200, 57600, 9600, …).

1 Like
13

OK thanks. I tried. but I am using windows terminal with "type comX" command.
I was selecting the serial speed via system configuration.
With the 3 it didn't work.
I tried unplugging and pluging the USB dongle back in after each time.

what would be a good windows application for doing this?

14

FYI router is just powered up via USB dongle UART 3.3V
so ground should be ok, or not?

15

Yes, you should ground, both devices need to be at the same [electrical] potential on the Serial wire for successful communication.

16

OK getting somewhere! 57600, I had to use the arduino IDE serial monitor.

17

U-Boot 1.1.3 (Sep 5 2017 - 14:14:14)

Board: Ralink APSoC 64 MB

relocate_code Pointer at: 83fa8000

enable ephy clock...done. rf reg 29 = 5

SSC disabled.

spi_wait_nsec: 29

spi device id: 20 70 17 20 70 (70172070)

Warning: un-recognized chip ID, please update bootloader!

raspi_read: from:30000 len:1000

*** Warning - bad CRC, using default environment

Press reset button to enter recovery mode.

Autobooting in 1 seconds

copying flash to 0x82000000

raspi_read: from:bc000000 len:800000

verifying uboot partition...

ok

verifying kernel and romfs partition...

ok

jump to 0xBC030000 ...

U-Boot 1.1.3 (Jan 23 2018 - 17:48:02)

Board: Ralink APSoC 64 MB

relocate_code Pointer at: 83fc0000

enable ephy clock...done. rf reg 29 = 5

SSC disabled.

spi_wait_nsec: 29

spi device id: 20 70 17 20 70 (70172070)

Warning: un-recognized chip ID, please update bootloader!

raspi_read: from:10000 len:1000

*** Warning - bad CRC, using default environment

============================================

Ralink UBoot Version: 4.3.S.0

ASIC 7620_MP (Port5<->None)

DRAM component: 512 Mbits DDR, width 16

DRAM bus: 16 bit

Total memory: 64 MBytes

Flash component: SPI Flash

Date:Jan 23 2018 Time:17:48:02

============================================

icache: sets:512, ways:4, linesz:32 ,total:65536

dcache: sets:256, ways:4, linesz:32 ,total:32768

The CPU freq = 580 MHZ

estimate memory size =64 Mbytes

raspi_read: from:20028 len:6

Autobooting in 1 seconds

Booting image at bc040000 ...

addr:0xbc040000

---- tpHdr = bc040000

---- text base = 80000000

---- entry point = 80000000

Uncompressing Kernel Image ... OK

No initrd

Transferring control to Linux (at address 80000000) ...

Giving linux memsize in MB, 64

Starting kernel ...

LINUX started...

18

Login incorrect
SLP login: user
Password:
Login timed out
Please press Enter to activate this console. ad
starting pid 6427, tty '/dev/ttyS1': '/bin/login'
SLP login: user
Password:
Login incorrect
SLP login: user
Password:
Login incorrect
SLP login: admin
Login incorrect
Please press Enter to activate this console.
starting pid 6498, tty '/dev/ttyS1': '/bin/login'
SLP login: user
Password:
Login incorrect
SLP login: user
Password:
Login incorrect
SLP login: user
Password:
Login incorrect
Please press Enter to activate this console. tpl
starting pid 6594, tty '/dev/ttyS1': '/bin/login'
ting pid 1143, tty '/dev/ttyS1': '/bin/login'
SLPSLP login: Password:
Login timed out
Please press Enter to activate this console.
starting pid 6146, tty '/dev/ttyS1': '/bin/login'
SLP login: admin
Login incorrect
SLP login: user
Password:
Login timed out
Please press Enter to activate this console. ad
starting pid 6427, tty '/dev/ttyS1': '/bin/login'
SLP login: user
Password:
Login incorrect
SLP login: user
Password:
Login incorrect
SLP login: admin
Login incorrect
Please press Enter to activate this console.
starting pid 6498, tty '/dev/ttyS1': '/bin/login'
SLP login: user
Password:
Login incorrect
SLP login: user
Password:
Login incorrect
SLP login: user
Password:
Login incorrect
Please press Enter to activate this console.
Login incorrect
SLP login:

searching for password at the moment.
any ideas?

19

Never connect Vcc of your usb2serial adaptor!

The router needs to be powered through its own/ normal PSU, the usb2serial adaptor can't provide enough power for it. You can only connect GND, RX and TX of the usb2serial adaptor, Vcc never, ever, gets connected.

20

ok thanks. it's powered through it's power supply. VCC of USB disconnected