DIY PRO firmware 3.7 won't create Wi-Fi hotspot (but firmware 4.2 will?)


I recently bought a DIY Pro Kit (version 3.7) and I have the following problem:
no matter what I do, no Wi-Fi hotspot gets created after flashing the firmware 3.7

Here is what I did so far:

  • flashing firmware 3.7 via my browser to the included D1 mini controller
  • flashing firmware 3.7 via my browser to a different D1 mini that I already own
  • flashing firmware 3.7 via Arduino IDE to both controllers.

I checked for the Wi-Fi hotspot with an Android phone, an iPhone, a Linux PC and a Windows PC!

→ nothing. No Wi-Fi network gets created.

Interestingly enough, when I flashed firmware 4.2 for testing purposes:


I just can’t figure out what’s wrong with firmware 3.7 and why it works on version 4.2.
I assume that it’s a firmware problem, since firmware 3.7 did not create a hotspot on two different D1 minis.

When comparing firmware 3.7 and 4.2 I don’t see anything that would indicate a different Wi-Fi configuration in the firmware.

Can someone help me with this problem please? I am at my wit’s end.

This is strange but we will have a look.

1 Like

Same issue here.

Just received two DIY-Pro kits and post-flashing via Chrome neither of the two Lolin D1-Minis fire up a Hotspot (used two android phones to scan).

Tried another Wemos D1 Mini (fresh out of the packet) and the same thing; no Hotspot.

The console log shows:

 ets Jan  8 2013,rst cause:2, boot mode:(3,7)

load 0x4010f000, len 3424, room 16
tail 0
chksum 0x2e
load 0x3fff20b8, len 40, room 8
tail 0
chksum 0x2b
csum 0x2b

 ets Jan  8 2013,rst cause:2, boot mode:(3,7)

load 0x4010f000, len 3424, room 16
tail 0

Any ideas?

You could also try to flash the firmware for the 4.2 version: The AirGradient DIY Air Quality Sensor (Pro Version PCB Version 4.2)

for some reason that one worked for me.

Thanks for the suggestion. As my target was to integrate with Home Assistant, I just went to Esphome which is working fine for me.

I have the same issue. does not work on 3.7 but does on 4.2. Is there any problem running the 4.2 version on the 3.7 DIY board?


Perhaps @Achim_AirGradient can correct me, but when I compare the firmware versions 3.7 and 4.2, they appear to be nearly identical. The only noticeable difference is that certain nested if statements have been transformed into else if statements.

So I guess there won’t be any issue running firmware 4.2 on a 3.7 PCB.

However, this raises an intriguing question: why is it that firmware version 3.7 does not generate a Wi-Fi hotspot, whereas version 4.2 does?

We could verify this issue and are investigating it. In the meatime just use the verson 4.2 which is partially compatible with the 3.7 PCB but the config button functionality might not work.

I updated the 3.7 version on our website at:


So if you have a PCB v3.7 please use above code to flash.

The software for the presoldered and soldered version is the same.

If you see the timestamp 2023.06.17 you should have the version you need.


That link does not work, and both the presoldered and soldered version do not have the 2023.06.17 in the title, and the link to both of those do not work. After flashing a hot spot is not opened.

I tried a third time and the 3.7 link worked and displayed as you have it above. Wierd?? Probably user error??