Issues with booting from named wedges, raidframe & NetBSD-9 (Regression from NetBSD-8)

[David Brownlee <abs%absd.org@localhost>]

I have a 'root on RAID1' setup NetBSD-8 box upgraded to NetBSD-9 which
no longer auto boots.

There are six disks in the machine, but the relevant dmesg entries are:

wd0: 5589 GB, 11628021 cyl, 16 head, 63 sec, 512 bytes/sect x
11721045168 sectors
dk0 at wd0: "raid0part0", 134217728 blocks at 2048, type: raidframe
wd2: 1863 GB, 3876021 cyl, 16 head, 63 sec, 512 bytes/sect x 3907029168 sectors
raid0: Components: /dev/wd2a /dev/dk0

So, this is a RAID1 with one partition on a gpt partition and another
on a disklabel (for historical incrementally upgrading reasons). In
both cases the partition is 1M from the start of the disk.

# disklabel wd2| ag ' a:'
 a: 134217728      2048       RAID                     # (Cyl.      2*- 133154*)

# gpt show -i 1 wd0
Details for index 1:
Start: 2048 (1M)
Size: 134217728 (64G)
Type: raid (49f48daa-b10e-11dc-b99b-0019d1879648)
GUID: 1680cacb-62e6-4f81-a31a-7211bb8e0a08
Label: raid0part0
Attributes: biosboot

Boots a NetBSD-9 kernel fine from NetBSD-8 boot blocks. Upgrading the
bootblocks to NetBSD-9 gives. (Mk.1 eyeball cut&paste)

NetBSD/x86 ffsv2 Primary Bootstrap

NAME=raid0part0 not found

>> NetBSD/x86 BIOS Boot, Revision 5.1.1 (Fri Oct  4 08:09:49 UTC 2019) (from NetBSD 9.0_BETA)
>> Memory: 635/3406336 k
Press return to boot now, any other key for boot menu
booting NAME=raid0part0:netbsd - starting in 0 seconds.
NAME=raid0part0 not found
open netbsd: Device not configured
boot: NAME=raid0part0:netbsd: Input/output error
booting NAME=raid0part0:netbsd.gz (howto 0x20000)
NAME=raid0part0 not found
open netbsd.gz: Device not configured
boot: NAME=raid0part0:netbsd.gz: Input/output error

If I then enter:
> boot hd0:
[booting occurs]

I'm not sure if this is related to the mix of wedge and disklabel
partitions in the raidframe, or something else. A workaround in this
case might be to fallback to traditional hdX: booting if the
bootblocks are unable to locate the named wedge - the "NAME=raid0part0
not found" error

David