In article <200007061206.e66C6MY03203@saruman.ics.muni.cz> you write:
>Couple of issues: amigappc,arm26,mac68k don't seem to pass/recognize
>any boot flags. Is the info passed other way ?

arm26 passes a binary structure from the bootloader to the kernel.  Look in
sys/arch/arm26/include/boot.h.

>evbsh3,mmeye,sh3,news68k,newsmips,sgimips,vax don't seem to
>get the boothowto eiher, seems like the only way to set the boot flags
>is reboot(2), whose flags are stored in non-volatile place. Or do
>I just overlook something ?

Well, in sys/arch/vax/vax/subr.s, the VAX seems to get its boothowto from
R11 on old bootloaders:

        movl    r11,_boothowto                  # Howto boot (single etc...)

On later bootloaders, it's passed in the RPB (in rpb_bootr5) (see locore.c):

        boothowto = prpb->rpb_bootr5;

-- 
Ben Harris
Portmaster, NetBSD/arm26