FAQ
TL;DR: BL602-based ELC-MNEW-01 flashes reliably at 460,800 baud, and “Maybe I will add functions for double-press or long-press.” [Elektroda, magic81, post #21825111]
Why it matters: This FAQ helps tinkerers flash, wire, and recover the Tuya/eWeLink mini relay safely and fast, with working pin maps and recovery tips.
Quick Facts
- Chipset and role mapping: BL602 with GPIO14=WiFi LED, GPIO21=Relay, GPIO20=Button1, GPIO3=Button2 (multipress indicated). [Elektroda, divadiow, post #21825740]
- Proven flashing figure: Max stable flash baud 460,800 via CH340 USB–TTL per user test. [Elektroda, magic81, post #21825111]
- Factory dump size seen: 2,097,152 bytes (2 MB) image extracted for analysis. [Elektroda, divadiow, post #21825740]
- UART console example: boot log reports uart0 at 2,000,000 baud. [Elektroda, divadiow, post #21825692]
- Quick recovery: hold GPIO20 (button) to trigger SafeMode; LED_Wifi_n indicates Wi‑Fi state. [Elektroda, magic81, post #21825111]
What board is this exactly—does ELC MNEW 01 match SM-028-V1.3?
Yes. A contributor identified it as another SM-028‑V1.3 unit in this family. This ties it to the same PCB revision and helps reuse known templates. [Elektroda, p.kaczmarek2, post #21825345]
What are the working GPIO assignments for relay, LED, and buttons?
High‑confidence mapping from the extracted DT data: GPIO14=WifiLED;0, GPIO21=Rel;1, GPIO20=Btn;1, GPIO3=Btn;2. The script labels originate from /config_gpio entries in the firmware. [Elektroda, divadiow, post #21825740]
What baud rate should I use for flashing and for serial logs?
Flashing worked up to 460,800 baud with a CH340 adapter. The BL602 firmware boot log shows uart0 configured at 2,000,000 baud for runtime logs. [Elektroda, divadiow, post #21825692]
Why didn’t SSID2 failover work after I set SSID and SSID2?
One user reported the device failed to connect to SSID1 and did not switch to SSID2, requiring a reflash for recovery. To avoid getting stuck, add a SafeMode long‑press handler. [Elektroda, magic81, post #21825355]
How do I add a SafeMode recovery so I don’t power‑cycle five times?
Use the start script to tie a long hold on the button to SafeMode and use LED_Wifi_n for status. How‑To: 1. Set LED to LED_Wifi_n on GPIO14. 2. Add: addEventHandler OnHold 20 SafeMode. 3. Reboot and test long‑press recovery. [Elektroda, magic81, post #21825111]
Can this firmware support long‑press or double‑press actions?
Yes. The author plans long‑press/double‑press, and the extracted config shows a button node with multipress mode, confirming support in firmware. “Maybe I will add functions for double-press or long-press.” [Elektroda, divadiow, post #21825740]
What useful info can we read from the boot log?
You can see SDK version, firmware name and version, and build date/time. This helps confirm images and debug mismatches after flashing. [Elektroda, divadiow, post #21825717]
How do you extract BL602 pin configuration from the firmware?
A work‑in‑progress script scans the BL602 image for a device tree blob and maps /config_gpio entries to human‑readable pins, then emits an OpenBeken‑style template. [Elektroda, divadiow, post #21825740]
Where should I upload my untouched factory 2 MB backup?
Share clean, unpaired dumps to the community FlashDumps repository. Avoid Wi‑Fi‑paired images to prevent leaking SSIDs. [Elektroda, p.kaczmarek2, post #21825361]
Why did Easy Flasher not extract JSON pin config like on some Tuya devices?
Because Easy Flasher only decrypts and extracts Tuya KV. This unit is eWeLink, so that Tuya‑specific config path doesn’t apply. [Elektroda, divadiow, post #21827062]
Any soldering advice to avoid lifting pads on this tiny board?
Trim wire ends short before soldering; long, stiff leads add leverage and can rip pads during handling or rework. [Elektroda, p.kaczmarek2, post #21825345]
What exact firmware build was observed on the dump?
Boot log shows FWSW‑WHBL602‑SWITCH‑BL602L_v1.2.0, built May 22, 2024, with release_bl_iot_sdk_1.6.34‑82. This correlates with the SM‑028‑V1.3 hardware. [Elektroda, divadiow, post #21825692]
What size is the stock image for this device?
The analyzed binary was exactly 2,097,152 bytes (2 MB). This aligns with common BL602 flash sizes used in these minis. [Elektroda, divadiow, post #21825740]
What if my UART output is garbage characters?
You are likely using the wrong baud. The observed boot log uses 2,000,000 baud; set your terminal accordingly to read clean output. [Elektroda, divadiow, post #21825692]
Is there a ready OpenBeken template from the dump?
Yes. The extractor produced a template with the GPIO map, suitable for importing into OpenBeken‑style workflows. Review and validate on hardware before deployment. [Elektroda, divadiow, post #21825740]
Can I use Easy Flasher for this BL602 and is it confirmed working?
Yes. A user successfully flashed this device with the community tool and reported it works well on this hardware. [Elektroda, magic81, post #21825355]
