esp devboard v1

I have a new ESP32 Wroom attached to my USB and it shows up in the settings on my mac:


I do have another ESP thing from sparkfun which I can access via /dev/cu.usbserial-DN02N1D8. This device I can flash without problems or read its mac address using esptool.py.


So I wonder how I can flash the ESP32.

Update: Added a picture of my board.

  • 1
    does the ESP32 contain a bootloader? ...... does it show up as a serial port?
    – jsotola
    Mar 7, 2019 at 2:07
  • I don't know for sure, but I would assume that it has a boot loader. It does not show up as an additional /dev/cu.XYZ entry, like the ESP-Thing does (/dev/cu.usbserial-DN02N1D8)
    – Besi
    Mar 7, 2019 at 10:08
  • @jsotola, why do you ask if it has a bootloader? as far as I know the Espressif chips have only serial upload so without a bootloader from factory they were useless
    – Juraj
    Mar 7, 2019 at 10:25
  • How have you attached the device? The esp wroom 32 is not soldered onto any kind of breakout board, so have you soldered wires to rx/tx?! Do you actually have a reset button? If not, there is no chance to flash it. When trying to flash without the esp being in program mode I would expect exactly what you are seeing
    – Sim Son
    Mar 7, 2019 at 16:27
  • you might have to hold some pins hi/lo to get it to flash. on some of my esp32 modules, that's holding down the flash button, on some it grounding a certain pin (0 i think) between starting the ide upload and actually uploading it, which is a bit of a balancing act. I recommend that once you get it flashed, use an OTA method to avoid the physical challenge.
    – dandavis
    Mar 7, 2019 at 18:06

2 Answers 2


I did fix the problem now.

My mac has USB-C and I was using a single USB-C to USB Dongle. And the serial port never showed up on my mac:

crw-rw-rw-  1 root  wheel   18,   5 Mar  8 10:53 /dev/cu.Bluetooth-Incoming-Port
crw-rw-rw-  1 root  wheel   18,   7 Mar  8 10:53 /dev/cu.Heinz-WirelessiAP
crw-rw-rw-  1 root  wheel   18,   3 Mar  8 10:53 /dev/cu.MALS
crw-rw-rw-  1 root  wheel   18,   1 Mar  8 11:02 /dev/cu.SOC

As soon as I used the Satechi USB Dock the Silicon Labs USB to UART port showed up in the list:

crw-rw-rw-  1 root  wheel   18,  13 Mar  8 11:04 /dev/cu.SLAB_USBtoUART

I can now communicate with the ESP32:

esptool.py --port /dev/cu.SLAB_USBtoUART read_mac

esptool.py v2.6
Serial port /dev/cu.SLAB_USBtoUART
Detecting chip type... ESP32
Chip is ESP32D0WDQ6 (revision 1)
Features: WiFi, BT, Dual Core, 240MHz, VRef calibration in efuse, Coding Scheme None
Uploading stub...
Running stub...
Stub running...
Hard resetting via RTS pin...

Please note that if you'll need the Drivers for the USB to Serial Chip from Silabs.

If you do not see the device showing up you'll need to load the kernel extension:

sudo kextload /Library/Extensions/SiLabsUSBDriver.kext/

After this you might to confirm the extension in the Privacy section of the mac settings. See this forum post for reference.


Flash ESP WROOM 32

kindly refer the link : https://docs.espressif.com/projects/esp-idf/en/latest/get-started/index.html#

  • Your link seems to have a typo in it.
    – Besi
    Mar 17, 2019 at 20:55
  • @Besi the link is corrected Mar 18, 2019 at 8:41

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