On Fri, Oct 25, 2013 at 19:40, Daniel Aurelio Galeazzo wrote: > Hi all, > > After ~1 year of OpenBSD without need your help (FAQ and man > are very complete) I've a question. I need to dual boot my HD > for Linux Distro (I need Android SDK and I red can't use it into BSD) > but I installed full crypt BSD since 5.3 via bioctl. It's not cleary for me > where bioctl run into boot process, if between 1° MBR and 1° PBR > bootstrap or beetween 1° PBR and 2° MBR (RAID) bootstrap.
It doesn't actually use bioctl. First, it helps to understand how a normal boot works. biosboot (/usr/share/mdec/biosboot) is the PBR. It gets copied into place by installboot. (the file on disk isn't used for booting.) bioboot loads /boot (this file is used) because it has an array of block numbers hard coded into it by installboot. (If you move, copy or delete /boot, your system will eventually stop working because biosboot will load the wrong blocks.) /boot reads the filesystem, loads the kernel, ... With crypto softraid: installboot copies /boot into a reserved area at the beginning of the softraid partition. In this case, the /boot file isn't used during booting. Then it copies biosboot into place, with the block array filled in with the locations of the copy of /boot. /boot will ask for your passphrase and decrypt the disk before loading /bsd. The usual trick for dual booting is to jump to or copy the PBR somewhere. That doesn't change with crypto.
