[OpenBSD/i386] 2 MBR Partitions with OpenBSD?

[Sylvain Briole]

Hi!

I have an IDE-Drive (hd0/wd0) on which I would like to install 2 different
installations of OpenBSD:
- one for tests
- one for daily work

I would like to separate these 2 versions as much as possible, on 2 different
MBR partitions:

Output of fdisk(8):
# fdisk wd0
    0: 00    0   0  0 -    0   0  0 [           0:           0 ] unused
    1: 00    0   0  0 -    0   0  0 [           0:           0 ] unused
    2: A6    0   1  1 - 1000 239 63 [          63:    15135057 ] OpenBSD
   *3: A6 1001   1  1 - 2585 239 63 [    15135120:    17826480 ] OpenBSD

I have already made 2 installations:
- one in the MBR partition number 2
  "test" OpenBSD
  /dev/wd0i : /
  /dev/wd0j : swap
- one in the MBR partition number 3
  "daily work" OpenBSD
  /dev/wd0a : /
  /dev/wd0b : swap
  /dev/wd0d : /tmp
  /dev/wd0e : /var
  /dev/wd0g : /usr
  /dev/wd0h : /home

My system boots perfect on the "daily work" partition, but I do not manage to
boot on the "test" partition:

installboot(8):
# cp /usr/mdec/boot /boot
# /usr/mdec/installboot -n -v /boot /usr/mdec/biosboot wd0
[...]
using MBR partition 3: type 166 (0xa6) offset 15135120 (0xe6f190)
[...]

How to tell installboot that I would like to boot from partition 2?

In thank you in advance,

Sylvain.