ESP32 Adafruit Feather V2 with w.FL and Qwiic not connecting

[Teascade]

Hello!

I don't know where else to seek advice, but I have an Adafruit board (ESP32 Adafruit Feather V2 with w.FL and Qwiic), which to my knowledge has has the ESP32-PICO-MINI-02U chip in it.

esptool seems to work fine with this chip, which makes me think the issue is not in the USB-cable, as with other cables even esptool ceases to work.

I.e.

 $ sudo esptool chip-id
esptool v5.2.0
Connected to ESP32 on /dev/ttyACM0:
Chip type:          ESP32-PICO-V3-02 (revision v3.1)
Features:           Wi-Fi, BT, Dual Core + LP Core, 240MHz, Embedded Flash, Embedded PSRAM, Vref calibration in eFuse, Coding Scheme None
Crystal frequency:  40MHz
MAC:                c0:cd:d6:38:6c:8c

Stub flasher running.

Warning: ESP32 has no chip ID. Reading MAC address instead.
MAC:                c0:cd:d6:38:6c:8c

Hard resetting via RTS pin...

However, espflash seems not to work, and I can't for the life of me figure out why:

 $ espflash board-info
[2026-05-27T18:19:08Z INFO ] Serial port: '/dev/ttyACM0'
[2026-05-27T18:19:08Z INFO ] Connecting...
Error:   x Failed to open serial port /dev/ttyACM0
  `-> Error while connecting to device

There isn't any more information that's even printed, no specific error codes or anything.

I've tried with espflash installed from crates that has version espflash 4.4.0, and also installing espflash directly from git, which also has version espflash 4.4.0. Neither work.

Please help?

[Teascade]

I actually figured that this was due to insufficient permissions given to espflash, and could be fixed by adding the uucp to my user. My bad.