I don't see any chip on the model you have selected. It is highly suspicious. You may have voltage issue.
Seriously ? 
Lots of advertised products are fake ones on such sites.
I'm using the one I noticed you, it works just fine. You may also use the CH340 as @KOA said.
@KOA @badulesia When I attempt to open the case, I see that Netgear has decided to "lock" the case by using a single special screw that requires some type of special tool. It's the one in the center. Very frustrating. Which is why Netgear put it there - to frustrate me. It appears to be some type of tamper proof security hex key bullshit. The hole that leads to the screw is deep and narrow, preventing the use a cheap bit set - it requires the highest quality (most expensive) narrow-shaft full-length L-wrench. Seeing this kinda makes me want to toss this shit in the garbage and never buy anything from Netgear again. If someone happens to know exactly which wrench to get for this, I might attempt it. I do not want to waste oodles of time trying out endless variations of tamper-proof hex and tamper-proof star drive sets. Netgear makes it very clear that they don't want anyone taking apart their stuff. Fυck Netgear.
Can you post a pic of the screw?
I used a cheap 1-dollar screwdriver set to open my Netgear router.
As for your this guide might help.
a similar router to yours. it uses a secure torx for the central screw.
https://www.amazon.com/torx-security-screwdriver-set/s?k=torx+security+screwdriver+set
@koa Here is a picture of my screw.
Here is picture of a secure torx screw sold at Lowes. They look like a match.
just get a cheap secure torx screw driver
@badulesia Do you see the serial port connections? I don't.
I took my router to a local tool store and tested one of their security torx drivers. Here are some photos of the guts. The lighting was poor so I am including multiple shots so that the shadows and highlights are in various places.
@chayote23
If I am not wrong, right in the middle, without any headers. Ask your local repair shop to solder the header pins, making your job easier.
And follow this scheme from 6700V2, and you can confirm using the multimeter method.
Electrical resistance between pins should be measured while the board is not powered.
Different hardware has different measured resistances between GND and other pins. However, there is often a common pattern as follows:
| Smallest to Largest Ohm | Ranges |
|---|---|
| GND to GND | 0 |
| GND to VCC | 5k ~ 200k |
| GND to TX | 8k ~ 2M |
| GND to RX | 10k ~ 8M |
I was about to post the same info. Right in the middle.
I wonder why this is not soldered out of factory. Some devices have, some not.
I have the R6260 and have soft bricked it many times upgrading with ddwrt. To recover I nmprflash back to stock firmware I download from the netgear website. The key here is the flash process can take up to 1/2 hour for some reason (blinking LED) before it reboots the router and I find myself back to stock firmware. Then I nmprflash again with ddwrt firmware.
That much! The worst I had was about 4 min for the R6220!
At this point, the power LED does not blink at any point during attempts to flash stock firmware with nmrpflash or tftp flash.
try and give it a while to complete the process. I noticed on my R6260 the stock firmware size was around 32MB. I think it completely wipes the flash and re-partitions the flash memory which takes a while.
Serial output?
In the end, I just could not stomach the required depth of technical work that this would require. I threw the Netgear AC2400 in the trash and ordered an Archer C7 on eBay. End of story. I hated to give up like that, but I have to choose my battles.
why thrash? I could love to work on this router. ship it over
Yes, why trash ? In one week you will find a solution and totaly regret doing so (I speak from experience).
my current Router was being bricked when upgrading to Openwrt 23 and was labled as almost unfixable by some experienced devs too but here it is running snapshot based on 23 thanks to @DragonBluep who fixed the issue and let me test it.
last year I faced issues with nmrp flash @jclehner was kind enough to fix it. https://github.com/jclehner/nmrpflash/issues/112
Openwrt is open source and is run by volunteers who are doing an excellent job. you just have to show some patience and look for help while providing the correct feedback/ history.
