Cannot upload to SAMD21_XPRO with Mbed framework

I can compile the mbed blink example but cannot upload
which USB port should I use ? The Debug USB or the Target USB ?

You need to use Debug port.

I tried but upload gives : Error: Please specify upload_port for environment or use global --upload-port option

I can see the serial port with ( pio serial ports list ) where it’s connected

/dev/cu.usbmodem1a122

Hardware ID: USB VID:PID=03EB:2111 SER=ATML2130021800004030 LOCATION=26-1.2
Description: EDBG CMSIS-DAP

if I use try to use a specific port like :
pio run --target upload --upload-port /dev/cu.usbmodem1a122

it reports a success but it’s a lie : the code is not uploaded

MacBook-Pro:SAMD21_XPRO ***$ pio run --target upload --upload-port /dev/cu.usbmodem1a122
[Tue Jul 26 14:04:48 2016] Processing samd21_xpro (platform: atmelsam, board: samd21_xpro, framework: mbed)

MethodWrapper([“upload”], [".pioenvs/samd21_xpro/firmware.bin"])
Looking for upload port/disk…
Manually specified: /dev/cu.usbmodem1a122
BeforeUpload([“upload”], [".pioenvs/samd21_xpro/firmware.bin"])
============================================== [SUCCESS] Took 0.89 seconds

even worse : I can specify ANY USB port and it reports a success too !

what am I doing wrong ?
thx

Please open an issue here GitHub - platformio/platformio-core: A professional collaborative platform for embedded development