Before installing grub, I always - better safe than sorry - try to
boot the OSes from the prompt.
Here I have a SATA disc:
Device Boot Start End Blocks Id System
/dev/sda1 1 37 297171 83 Linux
/dev/sda2 * 38 1254 9775552+ a6 OpenBSD
/dev/sda3 1255 30401 234123277+ 5 Extended
/dev/sda5 1255 1389 1084356 82 Linux swap /
Solaris
/dev/sda6 1390 1426 297171 83 Linux
/dev/sda7 1427 1463 297171 83 Linux
/dev/sda8 1464 1950 3911796 83 Linux
/dev/sda9 1951 2133 1469916 83 Linux
/dev/sda10 2134 3107 7823623+ 83 Linux
/dev/sda11 3108 5540 19543041 83 Linux
/dev/sda12 5541 6118 4642753+ 83 Linux
/dev/sda13 6119 30401 195053166 83 Linux
So, when I root (hd0,1,a) followed by chainloader +1, it boots to
OpenBSD splendidly.
But root (hd0,0) [ext2 filesystem], makeactive, kernel vmliuz--- ro
root=/dev/sda6, initrd ..., boot
dies with pivot_root ... cannot open /dev/console ... Kernel panic.
Yes, /dev/sda6 is '/'
What is it that I make wrong here ?