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:
Using the Arduino ESP8266 example called “CheckFlashConfig” shows the size of the flash to be 1MB:
I bent the LED out of the way and used a heat gun to remove the old chip.
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.
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.
Running the flash test sketch again after the change, shows I now have 4MB available: