BL602: Yiweilian/Sonoff 7-32V WiFi Relay DC7-32Pro Teardown and Flashing

Hi, I've purchaded this wifi relay from aliexpress (manual shows that it is a DC7-32Pro)
https://es.aliexpress.com/item/1005006511781009.html




If I put it in pairing mode (relay button for several seconds) it shows a SSID called ITEAD-1002129f4f

It listens port 80 TCP at 10.10.7.1 and shows a web with the message "SONOFF"
Ewelink app also recognizes it.
So, although aliexpress shows that is a Yiweilian, in fact it is an Sonoff

Probably there were more opened TCP ports, but as I wanted to try OTA update I've only scanned UDP ports

UDP 53 and 67 are always opened/filtered and there are another UDP port between 50.000 - 60.000 (different each boot)
OTA method didn't work for me, I tried:

but this doesn't do anything, netcat was doesn't show anything.

So I removed the chip board to look for UART programming ports:


And found them (TX, RX, BOOT, GND and 3V3)



And connected to serial port whith putty that shows me:


So I've installed BouffaloLabDevCube-v1.9.0 on my Ubuntu and tried to flash (booting it with BOOT pin connected to 3V3 using a 10Kohm resistor)



After reboot I can see OpenBL602_43C90001 SSID and then I can connect it I get the access to OpenBeken at http://192.168.169.1


Unafortunatelly, when I removed the IC miniboard from the board I removed also a small capacitor, I don't know how important is.




With this config:


I got:
- Red LED always blinking.
- When I push relay button the relay turns on for only 2 seconds, after that switches off.

But if I push it again before the 2 seconds, it switches off correctly.

I don't know how to solve that.
Perhaps is the capacitor that I've lost...

And also, when I try to detect GPIO with "GPIO Finder" the device stops responding IP, wifi is connected and button and relay are working but not web
or ping access.

- Any idea?

elbuit wrote:

Perhaps is the capacitor that I've lost...

is it gone gone or do you still have it around and could potentially repair?

divadiow wrote:

is it gone gone or do you still have it around and could potentially repair?

It's gone and I don't know the capacitance.
It was really small, so it should be a few nF.
I'll try to put another one with a similar "size"