How to reflash a web relay?

Question

Electronics

Good afternoon.
I bought a very popular web relay board on Ali. It connects via Ethernet and allows http requests to the desired addresses to open / close one of the 16 relays (there are also versions for 8 and 32 relays).

The question is: is it possible to flash the MK (is it possible to get the firmware somewhere), so that the relay closes immediately after a second after opening? (In order not to burn the castle). From which side to approach the issue? Is it realistic to check this or not?

Answer 1

It is possible to flash it, I see removable components there, in which, perhaps, the firmware lies.
Look for the firmware and modify it, but why not just send the relay close command after the relay open command?

Answer 2

There you have a Nuvoton chip, it contains firmware. If there are no lock-bits, take it via JTAG / SWD and read it. There are 5 sites next to Ethernet - I'm sure this is just for flashing and debugging the processor. Then some reverse engineering magic and a small patch.
That's just for sure the lock is worth it and you consider the firmware of the figs. First, write the exact marking (not visible in the photo) and find a datasheet on it

Answer 3

Reverse one of the versions of this device.
https://github.com/dpiegdon/SainSmart-REY-NET-v1.1

Answer 4

The easiest way to solve your problem (protecting the castle) is by "iron" methods.
If the lock is powered by direct current, then the first thing that came to mind:
Resistor - a large electrolyte - relay. When the relay is closed, the electrolyte will be discharged through the lock and open it. Then the resistor will limit the current, and even with the relay closed, the current through the lock will be very small. Select the denominations locally.