It is possible to specify some options and boot devices on the boot loader prompt:
boot [wd0a:netbsd]: [
device:] [
filename] [
-acdmqsvxz]
The default
device will be set to the disk that the boot loader was loaded from. To boot from an alternate disk or partition, the full name of the device should be given at the prompt.
device is of the form
xdNx where
xd is the device from which to boot,
N is the unit number, and
x is the partition letter of the NetBSD
disklabel(5) in the NetBSD partition of the MBR partitions. The
NetBSD boot loader recognizes FFS (both UFS1 and UFS2) and Linux Ext2fs.
The following list of supported devices may vary from installation to installation:
wd
IDE hard disks recognized by the Firmware.
The default
filename is
netbsd; if the boot loader fails to successfully open that image, it then tries
netbsd.gz (expected to be a kernel image compressed by
gzip(1)), followed by
netbsd,
netbsd.gz,
onetbsd,
onetbsd.gz,
netbsd.bak,
netbsd.bak.gz,
netbsd.old,
netbsd.old.gz,
netbsd.cobalt,
netbsd.cobalt.gz,
netbsd.elf, and finally
netbsd.elf.gz. Alternate system images can be loaded by just specifying the name of the image, so it is always a good idea to have a copy of working kernel in the
NetBSD root partition before trying a new kernel.
Options are:
-a
Prompt for the root file system device, the system crash dump device, and the path to
init(8).
-c
Bring the system up into the device configuration manager. From here the device locators can be tuned to the hardware; see
userconf(4).
-d
Bring the system up in debug mode. Here it waits for a kernel debugger connect; see
ddb(4).
-q
Boot the system in quiet mode.
-s
Bring the system up in single-user mode.
-v
Boot the system in verbose mode.
As the older version of the boot loader, it is also possible to specify options to the boot loader by breaking into the Firmware and using the “bfd” command:
Cobalt: bfd /boot/boot.gz [options]
The boot loader allows the following options:
nbsd= [device:] [filename] [-acdqsv]
The device, filename and options on the bfd prompt are same with the boot loader.
It is also a good idea to have a small rescue kernel in the
boot directory in the Ext2 partition for the Firmware boot. In an emergency case, this will allow you to use the Firmware ‘bfd' command to boot the rescue image:
Cobalt: bfd /boot/netbsd.gz