install/53291: GPT prevents installation

[martin%NetBSD.org@localhost]

>Number:         53291
>Category:       install
>Synopsis:       GPT prevents installation
>Confidential:   no
>Severity:       critical
>Priority:       high
>Responsible:    install-manager
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Wed May 16 08:30:00 +0000 2018
>Originator:     Martin Husemann
>Release:        NetBSD 8.0_RC1
>Organization:
The NetBSD Foundation, Inc.
>Environment:
System: NetBSD emmas.aprisoft.de 8.0_BETA NetBSD 8.0_BETA (EMMAS) #1: Fri Mar 2 13:16:40 CET 2018 martin%emmas.aprisoft.de@localhost:/var/nbsd/src-8/sys/arch/i386/compile/EMMAS i386
Architecture: i386
Machine: i386
>Description:

Sysinst is unable to install onto a disk that already has a GPT, even if
using MBR in full-disk-for-NetBSD mode and creating new partitions.

>How-To-Repeat:

On a scratch machine (or VM), boot into the RC1 installer (e.g. from CD image).
Use utility menu to run /bin/sh.

do:
  gpt destroy wd0
  gpt create wd0
  reboot

Boot into the installer again, do a standard installatin with full disk
for NetBSD, create new partition, accept all defaults.

After finishing the installer, remove installer medium and try to boot
from wd0 - it will fail (no PBR has been written, GPT protective MBR still
in place).

>Fix:
Should happen in sysinst. Manual workaround:

Go to utility, run /bin/sh, then do:

 > dd if=/dev/zero of=/dev/rwd0d count=100

Exit back to sysinst, go to main menu and do the installation.