No, it is not. boot(8) has no knowledge of usb.
On 2018 Jun 15 (Fri) at 15:18:29 -0400 (-0400), Filippo Valsorda wrote: :Is boot(8) on amd64 capable of using a ucom(4) device as a console for status and single user mode? I'd like to control the bootloader on a board without native serial ports. : :I tried "set tty ucom0" per FAQ 7 but it did not work. : :I suspect the answer is no, but looking for confirmation, or maybe workarounds I should know about. : :Thanks, :Filippo : :(Please keep me in Cc.) : -- A fanatic is one who can't change his mind and won't change the subject. -- Winston Churchill