Resolving the Wemos ‘espcomm_upload_mem failed’ error

Wemos espcomm errorA quick and easy fix for a constant offender

I usually write about projects I’ve made or things I’ve bought, but today I’m sharing a short post about an issue I continually experience with my ESP8266-based Wemos D1 Mini Lite and the Arduino IDE.

Every time I try to upload a new sketch to this board, the upload fails and it spits out an unhelpful ‘warning: espcomm_sync failed‘ message followed by an equally unhelpful ‘error: espcomm_open failed‘, and then finally an unhelpful ‘error: espcomm_upload_mem failed‘!

Not one, not two but THREE unhelpful error messages!

This doesn’t happen with any of my other Wemos boards, or even any of my other ESP8266 variants – just this ‘Lite’ model.

Anyway, the fix is easy, just apparently not permanent.

Connect power to your Wemos, then use a jumper wire to connect the GND pin to the D3 pin for 1 second. A paperclip or anything else conductive will do the job.

All you need is a single jumper wire to fix your Wemos’ confused brain

Once you’ve done that, disconnect power, wait another second, then power it up again.

That’s it – this fixes it for me every time and allows me to upload a sketch from the Arduino IDE, however if I then try to upload another sketch over that one the error comes back.

The fix is easy so I don’t mind doing this every time, but I wonder if this is an issue with just my Wemos D1 Mini Lite, or perhaps everyone is experiencing this and it’s a design flaw?

LOLIN (supposedly the official store for Wemos boards) appear to have stopped selling the Lite version – maybe this is why?

LOLIN have stopped selling the D1 Mini Lite

Whatever the reason, hopefully this helps a fellow maker or two with this annoying but easy to resolve issue.


1 Comment on "Resolving the Wemos ‘espcomm_upload_mem failed’ error"

  1. Bernard Sypniewski | 10/04/2019 at 22:53 | Reply

    I have encountered this problem so I’ll try this fix. I noticed (after 3 week of getting WINDOWS to give me a COM port) that the ARDUINO IDE (1.8.9) would properly download (with or without the above error) unless I said that my D1 Mini was really a LITE Wemos. I wonder why. With this lie, it works (except for the above error which seems to resolve itself around the third try).

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