I'm new to all this node mcu thing. I'm searching for relay shields because they're ready and well soldered, so I can put them into my light switches with no effort.

enter image description here

I've found this pack which already comes with the ESP and a custom firmware. I don't want to trust a strange firmware, I want to upload my own and play with it.

Can this ESP8266 ESP-01S's firmware be rewritten, and if so, which equipment I'll need?

link for the product

  • \$\begingroup\$ you can use an Uno to program it. or any usb serial adapter, like a cp2102 or ch340g. \$\endgroup\$
    – dandavis
    Jul 31, 2018 at 16:03

1 Answer 1


Do you see the black module ? It's just a generic ESP 8266 module (ESP-01, to be precise).

According to what I found on the Internet: Yes, you can.

For more information, you should read this.

  • \$\begingroup\$ I don't have a problem with it being generic. Do you mean I can update the official one, the generic one, or both? \$\endgroup\$ Jul 31, 2018 at 4:02
  • \$\begingroup\$ In short, yes.. \$\endgroup\$
    – Long Pham
    Jul 31, 2018 at 4:08
  • \$\begingroup\$ Wait... I didn't understand. The generic one can be updated? \$\endgroup\$ Jul 31, 2018 at 4:13
  • \$\begingroup\$ Yes, I think they all have serial bootloader. The only problem is the pinout, but in this case, yes. \$\endgroup\$
    – Long Pham
    Jul 31, 2018 at 4:33
  • 1
    \$\begingroup\$ For such small module, not all IC pins gets pinned out. But for this module, neccessary pins (for communicating with the host, doing firmware update) have been pinned out. \$\endgroup\$
    – Long Pham
    Jul 31, 2018 at 6:13

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