Interesting thing...
Any low-level experts here? 
sh-3.2# bless --info
Can't get device for /ht@0,f2000000/pci@9/k2-sata-root@c/@-1/@0:4,\grub\powerpc-ieee1275\core.elf: 3
Can't interpet OpenFirmware boot device
sh-3.2# bless --info /
finderinfo[0]:    149 => Blessed System Folder is /System/Library/CoreServices
finderinfo[1]: 1123302 => Blessed System File is /System/Library/CoreServices/boot.efi
finderinfo[2]:      0 => Open-folder linked list empty
finderinfo[3]:      0 => No OS 9 + X blessed 9 folder
finderinfo[4]:      0 => Unused field unset
finderinfo[5]:    149 => OS X blessed folder is /System/Library/CoreServices
64-bit VSDB volume id:  0xB89DF8F46183CAA8
sh-3.2# bless --info /Volumes/LeoGPT/
finderinfo[0]: 776593 => Blessed System Folder is /Volumes/LeoGPT/System/Library/CoreServices
finderinfo[1]:      0 => No Blessed System File
finderinfo[2]:      0 => Open-folder linked list empty
finderinfo[3]:      0 => No OS 9 + X blessed 9 folder
finderinfo[4]:      0 => Unused field unset
finderinfo[5]: 776593 => OS X blessed folder is /Volumes/LeoGPT/System/Library/CoreServices
64-bit VSDB volume id:  0x90889B45B79AB969
sh-3.2# bless --info /Volumes/
LeoGPT/      LeoSAS/      LeoServSAS/  Tiger-X/     TigerServ-X/ omv/         
sh-3.2# bless --info /Volumes/LeoServSAS/
finderinfo[0]: 103595 => Blessed System Folder is /Volumes/LeoServSAS/System/Library/CoreServices
finderinfo[1]:      0 => No Blessed System File
finderinfo[2]:      0 => Open-folder linked list empty
finderinfo[3]:      0 => No OS 9 + X blessed 9 folder
finderinfo[4]:      0 => Unused field unset
finderinfo[5]: 103595 => OS X blessed folder is /Volumes/LeoServSAS/System/Library/CoreServices
64-bit VSDB volume id:  0xBB6EB38C8A7B3F9F
sh-3.2# bless --info /Volumes/Tiger-X/
finderinfo[0]:   3321 => Blessed System Folder is /Volumes/Tiger-X/System/Library/CoreServices
finderinfo[1]:      0 => No Blessed System File
finderinfo[2]:      0 => Open-folder linked list empty
finderinfo[3]: 469372 => OS 9 blessed folder is /Volumes/Tiger-X/Applications/Utilities/System Folder
finderinfo[4]:      0 => Unused field unset
finderinfo[5]:   3321 => OS X blessed folder is /Volumes/Tiger-X/System/Library/CoreServices
64-bit VSDB volume id:  0x9168363BCCBD2E96
sh-3.2# bless --info /Volumes/TigerServ-X/
finderinfo[0]:   1707 => Blessed System Folder is /Volumes/TigerServ-X/System/Library/CoreServices
finderinfo[1]: 280476 => Blessed System File is /Volumes/TigerServ-X/System/Library/CoreServices/boot.efi
finderinfo[2]:      0 => Open-folder linked list empty
finderinfo[3]:      0 => No OS 9 + X blessed 9 folder
finderinfo[4]:      0 => Unused field unset
finderinfo[5]:   1707 => OS X blessed folder is /Volumes/TigerServ-X/System/Library/CoreServices
64-bit VSDB volume id:  0xCD351E8B70609054
As you can see - there are no blessed file, except 1 (& it's .efi 

 ). I always thought that BootX have to be blessed for MacOS startup? Where I can read a bit more details about blessed files & Powermac startup sequence? (I need better understanding, planning some linux reinstallations & so on...)