Hi, please review this change:

https://code.illumos.org/c/illumos-gate/+/2731

Currently it is not possible to boot from rpool which is installed on USB 3.0+ connected disk. On attempt to boot from rpool we get an error message 'Device is gone'.

This change prevents this error.

If you test this change, be sure that the boot disk is discovered as USB 3.0 or later (mdb -ke '::prtusb')