@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 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?
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.
@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.
I could not get it to work, just not enough storage and it is for a normal hobbyist quite impossible to solder many wires from a tiny CPU towards an external flash chip. it is not worth my time. Maybe you can create a managed switch from it, don't expect a web gui. But that breaks all the wireless functionality and requires a specific use case. it's not worth it, at least not for me.