NetBSD 9_RC1 not booting from disklabel partition on RAIDframe on GPT

[Matthias Petermann <mp%petermann-it.de@localhost>]

Hello,

there seems to be a deviation of the boot behavior in NetBSD 9_RC1 
compared to NetBSD 8.1 under the following circumstances:

1) system has 2 disks (wd0, wd1)
2) disks are GPT-partitioned
3) GPT contains one GPT-partition (RAIDframe component) each
4) RAIDframe raid0 contains a NetBSD disklabel

After installing NetBSD 9_RC1 it will not boot, instead the primary 
bootstrap is telling me:

	Unexpected raidframe label version
	NAME=sys0 not found

The closest I could find is this commit:

https://www.mail-archive.com/source-changes-d%netbsd.org@localhost/msg21099.html

where GPT and RAIDframe support for the boot loaders was enhanced (which 
is really good!).

Here is where I set up the system:

* Boot from USB installation media
* Select keyboard type
* Utility Menu - Run /bin/sh

    # ksh

    # gpt create wd0
    # gpt create wd1

    # gpt add -l sys0 -a 2m -s 96G -t raid wd0
    # gpt add -l sys1 -a 2m -s 96G -t raid wd1

    # gpt show -l wd0
    # gpt show -l wd1

    # dkctl wd0 listwedges
    # dkctl wd1 listwedges

    # gpt biosboot -A -i 1 wd0
    # gpt biosboot -A -i 1 wd1

    # vi /tmp/raid0.conf

        START array
        1 2 0

        START disks
        /dev/dk0
        absent

        START layout
        128 1 1 1

        START queue
        fifo 100

    # raidctl -C /tmp/raid0.conf raid0
    # raidctl -I 201912500 raid0
    # raidctl -i raid0
    # raidctl -A softroot raid0

* Exit shell and continue with installer

	* Install NetBSD to hard disk
	* Select raid0
    	* Select disklabel as partitioning scheme for raid0
	* Set sizes of NetBSD Partitions
        -> Change input units (MB)
		* root 16384
		* swap 16384
		* usr 32768+
		* var 8192
	* Bootblock: BIOS console
	* Installation w/out X11

* Utility Menu - Run /bin/sh

    # installboot -o timeout=30 -v -t raid /dev/rdk0 /usr/mdec/bootxx_ffsv2

* Reboot


Kind regards
Matthias