I tried soldering the onboard ROM with wires, and extend them to a board with MCP23017s. From that, these are connected to Raspberry Pi and does the job of getting the stuff out while the reset button is hold.
Unfortunately it doesn't work that way. I kept getting random values! The system possibly doesn't hold the address and data high-z during reset.
I have to remove the carrier board out. I would do a hot air, but I'm very unsure if high temperature could kill the contents inside, or it could kill the neighboring NOAC too. May have to resort to another stunt - low melt solder...
Suggestions are welcome here if anyone knows how to remove such a thing (check earlier logs on that carrier board).