Disable devices at boot time?

Thomas Mueller mueller6724 at bellsouth.net
Wed Oct 16 21:28:16 UTC 2013

Is there any way in FreeBSD to disable or enable devices on boot?

NetBSD has a flag -c (userconf) to boot that does this, if it works.

I tried it, but it immediately hung the computer, requiring Reset button.

Man page can be viewed at 


Section on userconf is

    -c   Sets the RB_USERCONF flag in boothowto.  This causes the
                    kernel to enter the userconf(4) device configuration man-
                    ager as soon as possible during the boot.  userconf(4)
                    allows devices to be enabled or disabled, and allows
                    device locators (such as hardware addresses or bus num-
                    bers) to be modified before the kernel attempts to attach
                    the devices.


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