Auto reset doesnt work propperly

[Sasha2018RL]

When I try to upload a new sketch to rp2040-zero (Waveshare) board using usb, arduino ide says that there are no available devices

No accessible RP2040/RP2350 devices in BOOTSEL mode were found.
Failed uploading: uploading error: exit status 249

How should I enable auto-reset support, thats mentioned in readme?

After the first upload, this should not be necessary as the arduino-pico core has auto-reset support. Select the appropriate serial port shown in the Arduino Tools->Port->Serial Port menu once (this setting will stick and does not need to be touched for multiple uploads). This selection allows the auto-reset tool to identify the proper device to reset. Them hit the upload button and your sketch should upload and run.

[dquadros]

It is working fine for me. I've just made a quick test with the rp2040-zero and the ASCIITable example sketch:

1. (First time using the board with the Arduino IDE) Connected the board with the BOOT button pressed, selected port UF2_Board and uploaded the sketch: OK
2. (After loading an Arduino sketch) Selected the serial port. Uploaded again the sketch: OK

The "auto-reset" is enabled by default after you loaded a sketch.