installboot(8) - NetBSD Manual Pages

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INSTALLBOOT(8)       NetBSD/amiga System Manager's Manual       INSTALLBOOT(8)


NAME

     installboot -- install a bootstrap on an FFS filesystem partition


SYNOPSIS

     /usr/mdec/installboot [-l newcommandline] bootblock device


DESCRIPTION

     installboot copies the bootblock to a bootable partition.  The bootstrap
     is written into the bootblock area on the partition, right in front of
     the superblock, and hence limited in size to 8192 bytes.

     The bootstrap resides in the first few blocks on the partition (as
     specified by Commodore-Amiga Inc.) The bootstrap is loaded into memory by
     the ROM from bootable devices: RDB devices, where the partition is marked
     as bootable, or (not on the DraCo) floppy disks in Amiga format
     (880K/1760k).

     In the presence of more than one bootable partition/floppy disk, the par-
     tition is chosen by the bootpriority (from the RDB), which can be over-
     ridden by the operator from the boot menu (on Amiga machines, hold down
     the outer mouse buttons during boot; on DraCo machines, press the left
     mouse button when prompted).

     On RDB devices, the whole bootblock is loaded by the ROM.  The number of
     boot blocks in the RDB partition entry must be correct.

     On floppy disks, the ROM always loads the first two blocks (1024 bytes),
     and the bootblock allocates memory and loads the whole bootblock on
     startup.

     After receiving control, the bootblock uses the stand-alone filesystem
     code in ``libsa.a'' to load the kernel from the filesystem on the parti-
     tion it was started from.  The code for the boot program can be found in
     /usr/mdec/bootxx_fd (floppy disk code), /usr/mdec/bootxx_ffsv1 (generic
     RDB disk code for FFSv1), or /usr/mdec/bootxx_ffsv2 (generic RDB disk
     code for FFSv2).

     The arguments are:

     -l newcommandline
                Specify a different command line to replace the default.

     bootblock  The file containing the bootblock (normally
                /usr/mdec/bootxx_ffsv1 or bootxx_ffsv2 for RDB devices).

     device     The name of the character special device specifying the parti-
                tion on which the bootstrap is to be installed.


EXAMPLES

     The following command will install the boot program for FFSv1 in the
     bootblock area on ``sd0a'':

           installboot /usr/mdec/bootxx_ffsv1 /dev/rsd0a


SEE ALSO

     dd(1), amiga/boot(8)


HISTORY

     The installboot command first appeared in NetBSD 1.3.


BUGS

     If installboot is accidentally used on the whole disk partition, the RDB
     will be overwritten, making your system unusable after the next reboot.

     Some third-party accelerator boards are not autoconfiguring.  You won't
     be able to use their memory when booting from the bootblock after a cold
     start.

     Some third-party disk controllers don't support bootblock booting.

     DraCo ROMs don't support bootblock booting from floppy disks.

     Most 68060 boards, unlike the DraCo, don't set the SysBase->AttnFlags bit
     for the 68060 CPU (a patch program which is called during AmigaOS startup
     does this).  You need to add options BB060STUPIDROM to your kernel to
     boot on such a machine.

     There is currently no easy way to edit the RDB from within NetBSD.
     Therefore, you have to use HDTOOLBOX or a similar tool to set the parti-
     tion to bootable, "use custom bootblocks" and the number of bootblocks to
     16 (for bootxx_ffsv1 or bootxx_ffsv2) or 2 (for bootxx_fd), at least the
     first time you install the bootblock.

     As normal dd(1) is used to install the bootblock, you can only install
     onto your currently used root (or any other mounted) partition from sin-
     gle-user mode, or while otherwise running in insecure mode.

NetBSD 10.1                    February 25, 2021                   NetBSD 10.1