install/54480: sysinst attempts to mount wrong disk

[venture37%geeklan.co.uk@localhost]

>Number:         54480
>Category:       install
>Synopsis:       sysinst attempts to mount wrong disk
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    install-manager
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Sun Aug 18 12:55:00 +0000 2019
>Originator:     Sevan Janiyan
>Release:        HEAD
>Organization:
>Environment:
NetBSD 9.99.9 i386 i386
>Description:
I have a i386 system with a CF card attached via USB multicard reader. CF card appears as sd1.
Running sysinst and choosing to upgrade the sd1 disk fails as it attempts to mount wd0 to /targetroot

The multicard reader presents several sd(4) devices which represents the different media slots.
sd0 is the sd card slot on this device but it's marked as drive offline. sd1 is the CF card slot.
>How-To-Repeat:
Attempt to perform an upgrade on a system with active devices numbered non-sequentially.
>Fix: