Upgrading Sonoff Wireless Smart Switch Flash Memory (ESP8266)

I’ve been playing around with the ESP8266 based Sonoff Wireless Smart Switch and I really wanted to upgrade the flash from the 1MB it comes with to 4MB so I can re-program it over wifi.

I’ve already got custom firmware running on it, but I don’t like the idea of opening it op and hooking it up to my PC each time I want to reprogram it. There is an Arduino library to allow updates via Wifi, but it requires a flash chip bigger than the 1MB the Sonoff comes with.

Luckily it’s pretty easy to change it. The replacement flash chip, is quite cheap. I got 10 for $3, with free shipping!

The one I used is a winbond 25Q32FVSIG

This is the Sonoff module before replacing the flash:

Sonoff with original Flash

Using the Arduino ESP8266 example called “CheckFlashConfig” shows the size of the flash to be 1MB:

Sonoff 1MB Flash

I bent the LED out of the way and used a heat gun to remove the old chip.

Sonoff Flash removed

Then I applied some flux to the pads and re-coated with solder, using my soldering iron with a fine tip.

Here is the new flash chip ready to be soldered into place, with the newly coated pads on the board.

Sonoff New Flash chip ready

Again using my soldering iron with a fine tip I heated up each leg until the solder flowed. I used tweezers to hold the flash chip in place and first did the two opposite corners.

Sonoff with new flash

Running the flash test sketch again after the change, shows I now have 4MB available:

Sonoff 4MB Flash



8 thoughts on “Upgrading Sonoff Wireless Smart Switch Flash Memory (ESP8266)”

  1. Hi Andre,

    Could you clarify what you have connected to the otherwise unpopulate RF pins? I know pin 1 and pin 2 are GND and 3v3, but what’s that other pin you’ve got a brown cable connected to?

    Thanks in advance!

  2. I see that you have an extra row of headers installeer. Could you Please tell me the correct gpio Numbers?

    I wan’t to use these pins for attaching external sensors like reed contact etc.

  3. This being a SOP8 chip, I should be able to flash it directly with my SP8-A usb programmer correct? I have the SOP8 adapter for it.

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