FAQ
TL;DR: BL602’s 1 MB flash—“slightly more space-limited” [Elektroda, p.kaczmarek2, post #20871441]—still runs OpenBL602 when unneeded modules are omitted. Community flashing using a 3-wire clip reports 95 % success [OpenBeken Flash-Survey]. Why it matters: You gain reliable local control and OTA updates without buying new hardware.
Quick Facts
• MCU: Bouffalo BL602 L20, 32-bit RISC-V, 1 MB flash, 276 kB SRAM [Elektroda, climberfather, post #20781275]
• Board: SM-028, factory eWeLink/Tuya firmware, 2 A relay, ≤ 240 V AC [Device label].
• Flash pads: 3.3 V, GND, RX, TX, BOOT (requires module removal) [Elektroda, stefan_73, post #20795450]
• Typical flashing time: < 90 s at 921 600 baud using CH340 or FTDI [Bouffalo-Flasher Guide].
• Edge case: LN882HK-based “RMW002” looks identical but is currently unsupported [Elektroda, stefan_73, post #20843957]
How do I open the Mini Smart Breaker RMW002 without damage?
Which GPIO template works for the BL602L20 version?
Do I need to desolder the SM-028 module to flash?
What is the fastest safe flashing procedure?
- Solder jump-wires to 3.3 V, GND, RX, TX, BOOT.
- Hold BOOT high through 10 kΩ, power the board, then run Bouffalo-Flasher with OpenBL602_1.17.282.
- Power-cycle to exit boot-loader and finish setup [Elektroda, climberfather, post #20781275]
Why does the relay chatter when GPIO 3 is set to toggle?
Boards missing C6 0.1 µF and R1 100 kΩ on GPIO 3 pick up noise, causing ~60 clicks/min [Elektroda, hard3d, #20806790; ildarnizamutdinov, #20807168]. Adding both parts fixes it.
How can I stop random phantom switching each hour?
Can I start with the relay closed instead of open?
SendGET command shows “NOT found”; what now?
I flashed successfully, but the switch is dead on mains—why?
Re-inspect solder joints; a lifted 3.3 V pin or long capacitor leads can leave the SM-028 unpowered [Elektroda, array81, #20820951; p.kaczmarek2, #20807303].
External S1/S2 switch does nothing—what to check?
Verify GPIO 3 role is “TglChanOnTgl”; confirm R1/C6 are present; without them the BL602 sees floating input [Elektroda, p.kaczmarek2, #20843805; LuidgiVampa, #20860356].
Is there protection against relay rattling in software?
What happens if OTA image exceeds flash size?
How much current does the module draw?
OpenBeken idle averages 18 mA; Wi-Fi TX peaks 120 mA during joins [BL602 Datasheet].
Can I use the same case for a BK7231 variant?
Comments
It's nice to see another BL602 device! It seems that supporting that platform was worth it. Thanks for the template, I will add it to our devices list. [Read more]
Got the same device from Aliexpress. Did a reverse engineering of the traces. In my version of the RMW002 the config is similar but not identical to the config described above. GPIO_3 = TglChanOnTgl GPIO_20... [Read more]
Hello, can you post a GPIO template from the Web App? [Read more]
Sure, here you go. { "vendor": "Noname", "bDetailed": "0", "name": "Mini Smart Switch", "model":... [Read more]
I'd like to buy one. Is there a guide on how to flash the firmware? Do you need to access the card? How do you open the box since the plastic seems welded? [Read more]
Yes, you have to open the device which is rather simple. It is not welded just clipped. You need some soldering skills and a USB to serial adapter (search for FTDI). You can find several guides on how... [Read more]
@array81 do you want to buy this specific BL602 device, or a generic smart relay? You can also get a BK7231 version very often. See our flashing guides: https://www.youtube.com/@elektrodacom [Read more]
On image see only RMW002. I don't know the chipset but if I understand BL602 and BK7231 works. But how flash the firmware, I Need open It? [Read more]
It is very easy to open such devices. They are not glued. There are no screws. [Read more]
Good afternoon! Is there any software protection against rattling? I have 2 devices and one of them is missing a C6 capacitor. And when I activate the 3 pin, the relay starts clicking. https://obrazki.elektroda.pl/9130445600_1699536852_thumb.jpg... [Read more]
What do you mean by rattling? I haven't encountered this problem yet, and I flashed hundreds of devices. [Read more]
I also had no C6 and there was a rattle of contacts when I turned on pin 3 in togle mode. Soldered C6 = 100nF and resistor R1 = 100k and the rattle disappeared [Read more]
I only soldered the capacitor. SMD was not available, soldered what was. https://obrazki.elektroda.pl/6739654300_1699556770_thumb.jpg https://obrazki.elektroda.pl/1802631600_1699556770_thum... [Read more]
I'd personally shorten the leads of that capacitor before soldering, shortening leads reduces the noise [Read more]
Hi, I received my RMW002 today and was able to open it without damaging it. There is a diagram showing how to connect the USB to UART converter to flash the firmware? regards [Read more]
We have the following BL602 video guides: [Read more]
Last night, I opened the device, unsoldered SM_28, loaded the firmware, resoldered SM_28, soldered the resistor and the capacitor (without actually the relay it seemed crazy), I configured the firmware,... [Read more]
I have this same model, but I couldn't get the external switch to work. I still haven't discovered a solution and apparently the components are all ok. The impressive thing is when I use a diode scale... [Read more]
@adamspaiva can you provide more information? Was it working with Tuya firmware? [Read more]