ESP32s2 Saola can't send data over USB but reception is fine.

[Czarneck]

Hello,
I have a question related to the ESP32s2 (Saola board with RGB)
I'm trying to run esp-idf/examples/peripherals/usb/device/tusb_serial_device/
But it doesn't work properly.
All the time I get flush errors even tho data reception from PC is fine.
Does anyone has an idea what's wrong?
Output is attached on the listing.

Code: Select all

I (1285488) example: Data from channel 0:
I (1285498) example: 0x3ffc0370   61                                                |a|
W (1285498) tusb_cdc_acm: flush failed (res: 0)
USBD Xfer Complete on EP 02 with 1 bytes
  CDC xfer callback
  Queue EP 02 with 64 bytes ...
I (1285778) example: Data from channel 0:
I (1285778) example: 0x3ffc0370   62                                                |b|
W (1285788) tusb_cdc_acm: flush failed (res: 0)
USBD Xfer Complete on EP 02 with 1 bytes
  CDC xfer callback
  Queue EP 02 with 64 bytes ...
I (1285988) example: Data from channel 0:
I (1285988) example: 0x3ffc0370   61                                                |a|
W (1285998) tusb_cdc_acm: flush failed (res: 0)
USBD Xfer Complete on EP 02 with 1 bytes
  CDC xfer callback
  Queue EP 02 with 64 bytes ...
I (1286178) example: Data from channel 0:
I (1286178) example: 0x3ffc0370   62                                                |b|
W (1286188) tusb_cdc_acm: flush failed (res: 0)
USBD Xfer Complete on EP 02 with 1 bytes
  CDC xfer callback
  Queue EP 02 with 64 bytes ...
I (1286368) example: Data from channel 0:
I (1286378) example: 0x3ffc0370   61                                                |a|
W (1286378) tusb_cdc_acm: flush failed (res: 0)

USBD Setup Received 00 03 01 00 00 00 00 00 
  Set Feature
    Enable Remote Wakeup
  Queue EP 80 with 0 bytes ...
USBD Xfer Complete on EP 80 with 0 bytes
USBD Suspend : Remote Wakeup = 1

On the pc side I'm using picocom without any switches.
I wonder if the board isn't broken somehow...
Is it possible that the reason is a faulty cable?
(I had to connect the specific gpio pins with USB A plug)
Thanks and regards!