multi-boot

[Lowell Gilbert]

doug at safeport.com writes:

> On Wed, 19 Oct 2011, Lowell Gilbert wrote:
>
>> doug at safeport.com writes:
>>
>>> I have a system with two physical disks with a version of FreeBSD
>>> installed on each disk. With various 7.x systems I had:
>>>
>>>   F1 disk1 on slices ads5x
>>>   F5 disk2 on slices ads6x
>>>
>>> I installed 8.2 on disk2, incorrectly saying leave the mbr alone. So
>>> when I boot from the second disk I get
>>>
>>>   F6 PXE
>>>   Boot:  F1
>>>
>>> I can then hit F1 or wait and all goes okay. I tried using sysinstall
>>> to rewrite the FBSD boot manager but that not effect any change. Must
>>> I rewrite the mbr on disk 1 also?
>>
>> That's what I would expect to have to do...
>
> Pre 8.2 the behavior the selected system just boot without the extra
> message. I had a 7.0 and a 7.4 system installed. I replaced the 7.4
> system with 8,2 With the boot setup I understand the FreeBSD boot
> manager would be on sector 0 track 0 of disk 1. The boot record for
> disk 1 is in the first logical sector for the drive. The boot record
> for disk 2 should be similarly placed on disk 2.
>
> What I think is missing is putting the boot manager on disk 2. If that
> is the case, is there a way to do that without reinstalling?

boot0cfg(8) from the system that does boot.  
Or boot in "rescue" mode from a CD (or other removable media) 
and use sysinstall.