---
level: start
order: 30
---

# First install, step by step

From an empty BIOS folder to games that start.

**You need:** internet and some free space. The installer says how much.

## 1. Open a terminal and paste

A **terminal** is a window where you type commands. Paste the line for your
system, then press Enter.

<Tabs syncKey="os">
<TabItem label="Windows">

Open the Start menu. Type **PowerShell** and open it.

```powershell title="PowerShell"
irm https://raw.githubusercontent.com/Abdess/retrobios/main/install.ps1 | iex
```

</TabItem>
<TabItem label="macOS">

Open **Terminal**. It is in Applications, then Utilities.

```sh title="Terminal"
curl -fsSL https://raw.githubusercontent.com/Abdess/retrobios/main/install.sh | sh
```

</TabItem>
<TabItem label="Linux">

Open a terminal.

```sh title="Terminal"
curl -fsSL https://raw.githubusercontent.com/Abdess/retrobios/main/install.sh | sh
```

</TabItem>
<TabItem label="Steam Deck">

Switch to Desktop Mode and open **Konsole**.

```sh title="Terminal"
curl -fsSL https://raw.githubusercontent.com/Abdess/retrobios/main/install.sh | sh
```

</TabItem>
<TabItem label="Android (Termux)">

Install **Termux**, a terminal app. Run these three lines in it.

```sh title="Terminal"
pkg install python
termux-setup-storage
curl -fsSL https://raw.githubusercontent.com/Abdess/retrobios/main/install.sh | sh
```

</TabItem>
</Tabs>

On Batocera, Recalbox and similar setups, see
[Get your files](../which-pack.md).

## 2. Check the setup it found

It opens a menu:

```
 RetroBIOS: Where do you play?
 Found on this machine:
 > <your setup>
   Another setup or folder
 BIOS folder: <its folder>
```

- **Right folder?** Press Enter.
- **Wrong folder?** Choose **Another setup or folder**, then browse to yours.
- **A handheld's SD card in a reader?** It is listed, as **muOS SD card**.

Arrows move, Enter chooses, Esc goes back. A controller's A and B do the same.

## 3. Install

The next screen counts the missing files and the free space.
Press Enter on **Install**. **Choose systems** keeps the consoles you
play.

**Old card?** In a card reader, choose **Copy the BIOS files from your old
card or a folder**, then the card. It stays unchanged.

## 4. Wait

B or Ctrl+C stops it. Run it again to carry on.

## 5. Read the result

- **Done**: all files are in place.
- **Finished with errors**: run the command again. It retries only those.
- **Nothing installed**: the screen says why. See [If it stops](#if-it-stops).

For questions line by line (screen readers), add `--plain`.

## What the command does

<!-- image: install-flow -->

## Check it later

Add `--check` to the same command. It changes nothing.

<!-- os-tabs -->
```sh
curl -fsSL https://raw.githubusercontent.com/Abdess/retrobios/main/install.sh | sh -s -- --check
```

All good:

```
  109/109 present (109 verified, 0 wrong hash)
```

## Undo

Files it replaces go to a `retrobios-backup` folder beside your BIOS folder.
The result says how to restore them.

## If it stops

### Nothing was found here.

Choose **Another setup or folder**, then your setup and its folder.

### Error: Python 3.8 or newer is required.

The message shows the command that installs Python. Run it, then run the
installer again.

A RetroPie 4.8 image has Python 3.7.3, and its update command finds nothing
newer. Run the command on a computer, with
`--platform retropie --dest \\RETROPIE\bios\`.

### Error: the downloaded installer does not match its expected fingerprint.

The download was cut short. Nothing was changed. Run the command again.

### Cannot create ...

You cannot write there. Do what the message says.

### The card is full

Nothing was written. Free some space, or choose another folder.

### The game still does not start

See [When a game does not start](troubleshooting.md).

## Next steps

- [Get your files](../which-pack.md)
- [When a game does not start](troubleshooting.md)
- Details: [Reading the installer's output, line by line](installer.md#reading-a-run)