Bought Netgear GS108T and need to block

Then I'd suggest getting help from someone with experience should it become necessary. Adding a header is simple enough, but it's probably better to play with a cheaper board first.

Lots of stuff I've never considered using, so I wouldn't know. Voice? CoS? Who cares? But all the important managed switch features are there. And much more, since you can run anything you want. Well, almost. It's not a very powerful device. After all it's only a switch :smile:

if you do attempt it... use single solid core CAT5 strands if you can get them... they are the easiest thing to punch through those filled in through holes for a beginner...

just don't bend them up too much or they'll snap internally...

once they are soldered in secure them on the board somewhere empty with hotglue...


As a sidenote: The top image in the Wiki was of the unsupported/unsupportable V2 revision with "ProSafe" branding and a "factory defaults" button on the front right -- the V3 has neither. I fixed that now to prevent mixups.
(Also thanks to @tmomas -- who apparantly doesn't sleep nor rest to keep the Wiki and the Forum in line -- for fixing up some media file shenanigans.)

IMNSHO: For signal wires just treat holes as solder points, add some fresh solder and tag on the wires. That's plenty strong for signal wires as long as you're not using them to hang the device from the ceiling. Going into the holes is really only needed if you want or need to insert header pins.


I bought a Zyxel SG1200-8 port smart switch from Amazon to get access to VLAN100 on the SG108Tv3.
It took a day of playing on the Zyxel SG1200-8 to chart out how to talk to a VLAN on a PVID access port.
I found out that a router loaded with Openwrt could do the same thing, if the router had a cooperating switch built in.
To be safe, like bmork, I soldered in 3 Berg pins into the SG108Tv3; it took an hour, even with the photo from
I had to scrape off solder flux and check for solder bridges around the dense pcb.
After soldering, I added the wire colors to the table as follows:

Pin Name
1 3.3V REDPL2303 (unconnected)
2 Tx GRNPL2303
3 Rx WHTPL2303
4 Gnd BLKPL2303

I can't remember, so follow bmork's advice and use the initramfs image.
I didn't have to block, because I used a 2nd (USB) adaptor set to to the switch at which blocked internet access.


Just to state the (hopefully) obvious, never rely on wire colours - while there are some customary choices around them, they're not standardized and may differ between vendors. Always make sure to confirm the actual allocation before. While you can (and often need to-) switch rx/ tx around, misplacing GND or Vcc can do real damage.

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I never use Vcc. GND can be found with an ohmeter. Knowing rx of the USB probe, I swap rx and tx around until I see output, then connect tx to the pcb. The C50v4 refuses to boot if rx and tx are reversed. :wink:

Maybe I am missing something. "" is a Google DNS server.

Also, I understand the device can demand access to call home while it has the original firmware but once it is running OpenWRT I cannot see how it can still be trying to "call home".

Again, sorry if I am misunderstanding the question.

Yes, is the Google DNS server, but the device instructions referred to blocking access in order to avoid the device insisting on registering itself with Netgear.

I wanted to get to know the built-in Stock firmware before "switching" to OpenWRT, without registration issue.

The OEM firmware upgrade to fixed the registration issue.

The rest here is about clarifying this device "switching" process, for which any input is much appreciated.

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Followed the instructions in the wiki and ended up with a soft brick. I then tried to solder a header without having proper de-soldering tools at hand, and messed up one of the holes. Sure, the latter is on me, but the former warrants the warning in the wiki, imo.

So you were unable to find out what caused the brick due to the console header issue? Or did you manage to get a boot log from it?

I managed to unbrick it by holding a jumper wire to a trace on the PCB and copy-pasting some commands with my other hand, but I unfortunately I have no boot log.

@stintel Would you be so kind to outline your jumper wire and copy-paste stunt, seems like useful info to reference for some of us.

This is to encourage others that might be undecided:

I also got myself such a switch now and can confirm that flashing succeeds just via Webinterface and without registration. I attached the switch to just a computer, no DHCP and no access to the Internet for the device.

The serial port was NOT necessary in my case. As always you should be aware that this MIGHT be needed if anything fails, but it is not a hard requirement anymore.