---
name: "installboot"
section: "8"
platform: "openbsd"
package: "man"
version: "8.0-current-20261101"
release: "OpenBSD 8.0-current (2026-11-01)"
platforms: ["openbsd"]
url: "https://new.carta.tech/installboot"
---

# installboot(8)

install bootstrap on a disk

## NAME

**installboot** – install bootstrap on a disk

## SYNOPSIS

**installboot** \[**-cnv**\] \[**-r** *root*\] *disk* \[*stage1* \[*stage2*\]\]

**installboot** \[**-nv**\] **-p** *disk*

## DESCRIPTION

**installboot** installs bootstrap on the specified disk. The exact process used depends on the system architecture, however there is generally a primary bootstrap (often known as a boot block) and a secondary bootstrap (often known as a boot loader). Some architectures only require a single stage bootstrap, which is written to the beginning of the disk.

The options are as follows:

- **-c**

  Set up the machine to boot from the specified disk by default. This is only implemented for amd64 and arm64 machines with UEFI firmware and GPT partition tables.

- **-n**

  Perform a dry run - do not actually write to the disk.

- **-p**

  Prepare filesystem. This will create a new filesystem on the partition reserved for the boot loader on architectures that require one.

- **-r** *root*

  Specify the mount point of the *root* filesystem to operate on, defaulting to */*.

- **-v**

  Increase verbosity during operation.

- *disk*

  Specify the *disk* to install the bootstrap on. This may be specified using a full pathname, an abbreviated disk form, or a disklabel UID.

- *stage1*

  Specify the file to use for the primary bootstrap. If not specified, the default for this architecture will be used.

- *stage2*

  Specify the file to use for the secondary bootstrap. If not specified, the default for this architecture will be used.

## EXAMPLES

In its most basic form, to install bootstrap on *disk* sd0, using the default primary and secondary bootstrap files:

```
# installboot sd0
```

To install bootstrap on an OpenBSD amd64 machine, using */usr/mdec/biosboot* as the primary bootstrap and */usr/mdec/boot* as the secondary bootstrap:

```
# installboot -v wd0 /usr/mdec/biosboot /usr/mdec/boot
```

## SEE ALSO

[disklabel(8)](/disklabel/8.md)