Re: install/53291: GPT prevents installation

[John Nemeth <jnemeth%cue.bc.ca@localhost>]

On May 16,  8:30am, martin%NetBSD.org@localhost wrote:
}
} >Number:         53291
} >Synopsis:       GPT prevents installation
} >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).

     Is this possible confustion with a UEFI disk as UEFI doesn't use
PBRs?  GPT with UEFI and GPT without UEFI use considerably different
mechanims to boot.

} >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.
} 
}-- End of excerpt from martin%NetBSD.org@localhost