Thank you!
I seem to have some issues with J-Link. I did this in my environment:
[env:teensy31]
platform = teensy
board = teensy31
framework = arduino
build_flags = -D USB_FLIGHTSIM_JOYSTICK
debug_tool = jlink
upload_protocol = jlink
and when I hit the —> button after compiling I got this:
J-Link Command File read successfully.
Processing script file...
J-Link connection not established yet but required for command.
Connecting to J-Link via USB...O.K.
Firmware: J-Link V10 compiled Apr 23 2020 16:49:14
Hardware version: V10.10
S/N: 260106418
License(s): FlashBP, GDB
OEM: SEGGER-EDU
VTref=0.000V
Target connection not established yet but required for command.
Device "MK20DX256XXX10" selected.
Connecting to target via SWD
Cannot connect to target.
Now the device is an MK20DX256VLH7, not XXX10. How did that change?