I have a freenas-boot / stripe / da6p2 boot device (usb stick) working correctly.
I have inserted a new USB device "da5" correctly detected (note: I tried all USB ports of my computer).
glabel status returns (I removed other disks):
gptid/a0daaf02-7e84-11e6-a889-78e3b5ce431f N/A da6p1...