This is a tool for patching the SPI flash contents present on Netgear GS108v4 switches to make them 802.1Q-VLAN-capable. See this blog post for technical details.

First, you need some way to dump the current flash contents from your switch. My recommendation is to get a SOIC-8 clip, put stm32-vserprog on a Bluepill board and then use Flashrom for reading and writing the flash.

You can of course use any other tool that accomplishes the same goal, but this will probably give you the best experience for the least amount of money. Please note that all flashrom commands in this document are specific to stm32-vserprog and might need modification if you use some other interface.

Important: Make sure the switch is disconnected from it's power supply before attaching the programmer. Otherwise, the ASIC and the programmer will interfere when accessing the flash.

Attach the SOIC-8 clip to the flash chip. Make sure the orientation is correct: Pin 1 of the cable is usually marked in some way, pin 1 of the flash has a circular indentation on the body of the chip and a dot on the PCB next to the pin.

Then run:

flashrom -p serprog:dev=/dev/ttyACM0:115200 -r original.img

This should give you the current contents of the switch's flash. Make sure not to lose it so that you can revert to the original state if necessary.

Create a VLAN config file. example.cfg provides an example how to do so.

Run ./apply.py original.img my-vlan.cfg modified.img. The tool will print a table representing the generated VLAN config. Check to make sure it matches your expectations.

If the tool reports an unknown flash image, please consider creating an issue and attach your image file.

Flash the new image using flashrom -p serprog:dev=/dev/ttyACM0:115200 -w modified.img.

Disconnect the programmer and power up the switch. Test your configuration to make sure it behaves as expected.

If you encounter any problems, feel free to create an issue or send a pull request. Thanks!