Category Archives: ESP32

Cannot Flash Wemos ESP32 D1 Mini

I have just had an issue where I couldn’t flash my ESP32 Wemos D1 mini, It was giving me the following error:

Failed to connect to ESP32 invalid head of packet 0x65

which I believe is similar to other similar errors like:

Invalid head of packetĀ (‘S’)

Invalid head of packet (‘w’)

Invalid head of packetĀ (‘p’)

There were a number of different suggestions online including:

  • Try lowing the Baud rate
  • Try pressing the reset button on start
  • Try pressing the boot button (there isn’t one on the Wemos D1 Mini)

However, the one thing which worked for me to was short IO0 to GND while Arduino flasher was trying to connect to the board. That allowed it to programme.

FIXED: Arduino IDE High CPU Usage

I’ve been using the Arduino IDE for some project development recently, and finding that I’m getting very high CPU usage from Java to the point that it’s slowing my machine down, and then Arduino IDE becomes unresponsive. I couldn’t find any info on any of the forums related to this, but from my own research I believe I have found the problem.

It seems that my problem comes after a long time connected to the Serial Monitor and receiving data from the Arduino. It then gets worse and worse until things start getting unresponsive. The solution for me appears to be to basically just close the Serial Monitor, and reopen it. this can sometimes take a long time, and has caused Arduino to become unresponsive before, causing it to crash and restart. However, this appears to have been the only time I have seen this problem online.