Improve port-related upload error messages #3075
Description
Describe the request
The upload error message on macOS is confusing when bossac cannot open the port.
When uploading to a MKR1000 board on macOS, arduino-cli reports:
No device found on cu.usbmodem1101
even though the selected port is /dev/cu.usbmodem1101. This is technically correct, but from a user perspective, it looks like the CLI is using a different port than the one they specified.
Describe the current behavior
./arduino-cli version
arduino-cli Version: git-snapshot Commit: 49772829 Date: 2026-01-10T11:58:14Z
./arduino-cli board list
Port Protocol Type Board Name FQBN Core
/dev/cu.Bluetooth-Incoming-Port serial Serial Port Unknown
/dev/cu.debug-console serial Serial Port Unknown
/dev/cu.usbmodem1101 serial Serial Port (USB) Arduino MKR 1000 WiFi arduino:samd:mkr1000 arduino:samd
/dev/cu.usbserial-0001 serial Serial Port (USB) Unknown
./arduino-cli upload --fqbn arduino:samd:mkr1000 --port /dev/cu.usbmodem1101 ~/dev/git/boardlab/test_workspace/monitor --verbose --log-level trace
Performing 1200-bps touch reset on serial port /dev/cu.usbmodem1101
Waiting for upload port...
No upload port found, using /dev/cu.usbmodem1101 as fallback
No device found on cu.usbmodem1101
"/Users/xxx/Library/Arduino15/packages/arduino/tools/bossac/1.7.0-arduino3/bossac" -i -d --port=cu.usbmodem1101 -U true -i -e -w -v "/Users/xxx/Library/Caches/arduino/sketches/002302D32EBDB868619B7ECAC4E71903/monitor.ino.bin" -R
Failed uploading: uploading error: exit status 1
Arduino CLI version
Operating system
macOS
Operating system version
15.7.3
Additional context
When I do the upload via gRPC, sometimes I get a different port error; /dev/cu.usbmodem1101 vs. /dev/tty.usbmodem1101
Performing 1200-bps touch reset on serial port /dev/cu.usbmodem1101
Waiting for upload port...
Upload port found on /dev/tty.usbmodem1101
No device found on tty.usbmodem1101
"/Users/xxx/Library/Arduino15/packages/arduino/tools/bossac/1.7.0-arduino3/bossac" -i -d --port=tty.usbmodem1101 -U true -i -e -w -v "/Users/xxx/Library/Caches/arduino/sketches/002302D32EBDB868619B7ECAC4E71903/monitor.ino.bin" -R
Failed uploading: uploading error: exit status 1
Issue checklist
- I searched for previous requests in the issue tracker
- I verified the feature was still missing when using the nightly build
- My request contains all necessary details