install/54934: Command fail in sysinst on computer with MS Windows 10 and NTFS partitions

[i@-.-]

>Number:         54934
>Category:       install
>Synopsis:       Command fail in sysinst on computer with MS Windows 10 and NTFS partitions
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    install-manager
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Tue Feb 04 16:35:00 +0000 2020
>Originator:     guest01
>Release:        9.0_RC2
>Organization:
-
>Environment:
amd64
>Description:
When you try to install NetBSD on computer with Windows 10 and NTFS partitions, the procedure is stopped with command fail and installation can not be continued.
After that, when you try to repeat procedure you will see that FFSv2 partition is created but the procedure will stop the same way.

Sorry, I don't answer emails. You can close the report if it is useless.
>How-To-Repeat:
1	 Boot computer with system installation disk
2	 Select Install NetBSD
3	 Keyboard type: US-English
4	 Install NetBSD to hard disk
5	 Shall we continue ? Yes
6	 On which disk do you want to install NetBSD ? wd0 (149G)
7	 This is the correct geometry
8	 Use the entire disk
9	 Shall we continue ? Yes
10	 Use default partition sizes
11	 Partition sizes ok
12	 Shall we continue ? Yes
13	 Selected bootblock: BIOS console
    	 Continue
14	 Status: Command failed
	 Command: /usr/sbin/installboot -o console=pc,speed=9600
                  /dev/rwd0a /usr/mdec/bootxx_ffsv2
	 Hit enter to continue
	 installboot: Old BPB to big, use -f (may invalidate filesystem)
	 installboot: Set bootstrap operation failed
15	 Warning: disk is probably not bootable
	 >Hit enter to continue
16	 You are back at screen with:
	 a: Install NetBSD to hard disk

After that, you can try to repeat the procedure and you will see that FFSv2 partition is created but procedure will stop the same way.

Then you can see:
1    e: Utility menu
2    d: Partition a disk
     You have displayed:
     a: wd0 (149G)				UNCHANGED
     b:     wd0a on / (FFSv2) (unused)		147G
     c:	    wd0b (swap)	      			2038M
>Fix: