TP-Link TL-WR820n V2 (EU)

Dear readers, I found a very cheap interesting little router and bought it.
The TP-Link TL-WR820n V2 (NL)

I made pictures of everything, box, cables, router, mainboard. chips, serial connection points.

How do I add this thing to the wiki?
I am willing to fry this thing to get OpenWRT support.

Soc: MT7628KN
Flash: cFeon QH16B-104HIP

Soc: https://www.mediatek.com/products/homeNetworking/mt7628k-n-a
Flash: searching, i think it's just 2MB but luckily SMB. Maybe we can find a working 4 or 8MB chip to solder on.

With kind reagards
Winos.

Edit, I will update this post with more information later today.

It is not going to be possible to run OpenWrt on that model. MT7628K has internal RAM 8MB not expandable, OpenWrt requires at absolute minimum 32MB.

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@mk24, thank you for your information.
As some of you might know I am quite stubborn and so I refuse to declare the TL_WR820n V2 (EU) as a piece of plastic. Although it's the most useless router I found so far. I mean, you have to replace everything except it's ticking heart. We are on the OpenWRT forums after all.

Positive mode on

  • I found the full datasheet of the SoC, it seems to support external ram, higher flash and USB
  • I did not change the flash chip or any firmware so I can make a back-up
  • The SoC runs somewhere between 575 and 580Mhz which is complete overkill for this thing.
  • I can replace the flash chip with a 64Mbit, approx. 8Mbytes (same brand)
  • An external ram chip is supported, well; let's test that!
  • I believe the antenna's are replaceable even though TP-Links says no
  • There is space in the housing.

Reason,
I know the theory, not the practice. let's learn.

Extra reason:
It's mine, I determine the boundaries, not TP-link.

I have one remaining question.
Which flash chip do you recommend.

I was looking at the MT7628KN on a ZBT manufactured router. The spec sheet does say it supports DDR(1) RAM upto 64Mbytes
MT7628 Data sheet

I think OpenWRT on these devices will hinge on whether the manufactured board has the external RAM circuit.

@shep

I know and so I ordered all the necessary tools to make a dump from the current chip. I will upgrade the current 16Mbit chip to a 64Mbit chip. This gives me enough storage.

Since my device has no external ram chip I will have to solder an external one directly to the SoC. Do you know which SMD chip I can use?

FLASH chips typically have 8 pins and are not too difficult to upgrade.

On the other hand, the number of pins on a RAM chip is 60+. Without the circuit printed on the board it is going to next to impossible.

https://www.mouser.com/ProductDetail/Micron/MT46V32M16P-5B-ITJ?qs=rrS6PyfT74e%2FLws3B2S%252Bzg%3D%3D

Some of the other versions of this do have external ram

See the photos for V4, v5, v6

https://wikidevi.wi-cat.ru/TP-LINK_TL-WR840N_v6

@shep
Unfortunately, mine does not.

I know that by trying this I do not contribute to anything useful other than my own experience. However, this may lead to useful future projects since the costs are low, the difficulty for that device is high and personal experience skyrockets.

If you look closely at the wikidevi link above, there are too-many-to-count "wires" from the RAM chip to the CPU. You may learn a lesson attempting this - but likely not the one you had in mind.

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@shep
Just 66 wires to solder with 132 joints. It will be nearly impossible by hand but I am going to try it.
First with the flash chip, then with a ram module though It will take some time.

If somehow I make it possible with a 64Mbyte SMD chip, there will be 8 free Mbytes from the SoC.

Most likely it will fail.

The flash chip just has 8 joints and there are some Youtube videos on the process
https://www.youtube.com/watch?v=v7Eep5Renog

Update:
Currently waiting for the last supplies to arrive although ram will be annoying to solder. I still have to come up with a solution for that.