The ESP32 has a bluetooth stack, but the manufacturer (EspressIf) is still finishing their software implementation to manage it.

It's not a limitation of the M5 hardware, it's just that the existing Arduino libraries are dependent on the processor's specific hardware registers in order to function. Until EspressIf finishes their work and publishes it, support for Bluetooth on any ESP32 based platform will be limited.

If you use PlatformIO instead of the Arduino IDE, you could potentially use EspressIf's Dev Platform but you wouldn't be able to use the M5Stack Libraries without some work.

The Bluetooth hardware options have really been expanding lately, but the software side needs to catch up.

@stanszal 在 Simple fix when upload fails. 中说：

I am using win7 and arduino ide 1.8.5. The board automatically selects the com port when plugged in . The port varies .
I have the cap soldered onto dupont leads and have them plugged all the way in. I tried both polarity's

I keep getting the "timed out waiting for packet header " error. for whatever reason it won't connect. I have no problems with the ports with various Arduino boards, ESP8266's and ESP32's

As a note, I am having the exact same problem. I'm using PlatformIO, but the esptool output is the same indicating the same underlying error.

When I look at the Serial Monitor, it's booted and here is the output:

rst:0x1 (POWERON_RESET),boot:0x13 (SPI_FAST_FLASH_BOOT)
configsip: 0, SPIWP:0xee
clk_drv:0x00,q_drv:0x00,d_drv:0x00,cs0_drv:0x00,hd_drv:0x00,wp_drv:0x00
mode:DIO, clock div:2
load:0x3fff0018,len:4
load:0x3fff001c,len:812
load:0x40078000,len:0
load:0x40078000,len:11404
entry 0x40078aa0
user code done

I recovered mine using the EspressIF ESP32 Download Tool following the M5 guide for loading their MicroPython / Cloud IDE firmware.

I wanted to play around with their cloud IDE anyway, but you should be able to use the factory firmware (also on GitHub) or one of the ones in your Arduino compile cache that you know works.

Edit: Forgot to mention, I did have to use a 10uf cap across the GND and RST pins as described earlier in the thread in order to get the EspressIf tool to be able to connect.