Can't upload with esptool.py to M5Atom on macOS Big Sur

[blackketter]

I'm having trouble with uploading to an M5Atom using esptool.py on macOS Big Sur 11.2.2 with the error:

A fatal error occurred: Timed out waiting for packet header

I've tried to use the Updater_FW20200422 (suggested in another thread), but get another error with that tool:

Detecting M5Stack products.
Find M5Stack products.
Kernel driver deteched.
Apply magic success.

Fail to cast magic stage 2, please contact vendor.
Waiting for device in DFU mode.....................%

Otherwise the serial port works and I am able to use esptool.py to read_mac:

dean@lucky13 razzle % esptool.py --port  /dev/cu.usbserial-7D52471593 read_mac
esptool.py v3.0
Serial port /dev/cu.usbserial-7D52471593
Connecting....
Detecting chip type... ESP32
Chip is ESP32-PICO-D4 (revision 1)
Features: WiFi, BT, Dual Core, 240MHz, Embedded Flash, VRef calibration in efuse, Coding Scheme None
Crystal is 40MHz
MAC: 50:02:91:92:3e:e8
Uploading stub...
Running stub...
Stub running...
MAC: 50:02:91:92:3e:e8
Hard resetting via RTS pin...

Any suggestions on how to proceed?

[blackketter]

Also, I updated the CP210x Macintosh OS VCP Driver to v6 and that didn't help.

[felmue]

Hello Dean

according to the description the M5Atom requires an FTDI driver.

Note: I don't have a Big Sur installation, so I cannot tell if that will actually help.

Cheers
Felix

[blackketter]

Thanks for the suggestion, @felmue, but I figured out the problem!

The default baud rate of 460800 is too fast for this device. If I specify --baud 115200 (in platformio.ini, that would be upload_speed = 115200) it works.

Maybe this will be useful to someone else in the future.