ESP8266 Community Forum

I bought a wifi wall dimmer that I was guessing had an ESP8266 and if it did I thought it was a sure thing that I could flash it with something like tasmota. Well, it has an ESP8265, and as far as I can tell with my microscope there are no connections to pins 25 and 26 (U0TXD, U0RXD). There are connections to SD_Data_2 and 3 (pins 18 and 19) so my question is - can I get into flash mode over a serial connection using 18 and 19 or do I have a board that was not made for access to the usual serial pins? How would they have flashed this thing in a production setting without having access to 25 and 26?

They would most likely have burnt the flash before even mounting it on the PCB.

If you can find the serial port and communicate back and forth with it, then you may be able to flash the unit as the data is expected to be sent over the serial. However, there's a chance they remap the serial pins after startup, in which case you'll be out of luck.

Also you will need access to the RESET, GPIO 0 and GPIO 2 pins to get it into flash mode. I doubt that will be possible. They might be tight to GND. If there is a resistor, you may be able to pull it really hard to V+.

Here is a photo of the board. The chip is actually ESP8285, which I guess means it has internal sram (1 mb). Which again has me wondering how these chips are flashed during board assembly. Are they somehow flashed before soldering?

This board has a "Mobu W6-1014" chip (16-pin) that I have no clue what it's for. It might be wired up to the nearby ATMEL608. The 6-pin header with pins is for connection to the main-power board (3 control signals for 3 relays, 1 ground and 1 VCC maybe 5 v I haven't measured it). There are a couple of pad areas (8 pads plus a resistor) that might be for flashing? If it will help, I can take some time to trace where on the 8285 these pads go if there's interest here to understand this board.

I bought a few of these on ebay, and according to the product details on the ebay page the Make is "MUCH(r)". It uses an eWelink app to control it. I have since ordered a few other switches from another vendor, this time the Make is "Sonoff" - I home these are more understandable from a flashing pov.

Regarding the "Mobu" chip - I've come across the "Mobu official store" on Aliexpress, and these are wifi wall switches. Seems more than a coincidence that there is a "Mobu" brand of wifi wall switches AND a chip with "Mobu" on it.