# Adding BIOS files

Some emulators require BIOS files to work correctly. 

### Location

As a general rule, BIOS files must be copied to the `\bios` subfolder of the Retrobat folder:

<div align="left"><figure><img src="https://i.imgur.com/5vAbqqT.png" alt=""><figcaption></figcaption></figure></div>

{% hint style="info" %}
Some systems need the bios files to be placed in subfolders or in other places. Refer to the individual system wiki page for detailed information about BIOS placement.
{% endhint %}

### Missing BIOS check

RetroBat has a "missing bios check" function available from the [GAME SETTINGS](/navigation/main-menu.md#game-settings) in the [MAIN MENU](/navigation/main-menu.md):

<div align="left"><figure><img src="https://i.imgur.com/wXO2Ier.png" alt=""><figcaption></figcaption></figure></div>

The missing BIOS appear with a broken chain icon. The ones where the md5 hash is not listed by Retrobat will appear with a ![](/files/CcGMIlOvTIoRAzLjJmpL) icon, however the latter still can work.

<div align="left"><figure><img src="https://i.imgur.com/0TLxbBh.png" alt=""><figcaption><p>5200.rom is missing</p></figcaption></figure></div>

{% hint style="info" %}
The detailed list of required BIOS for each system can be found in the individual [Game System section of the wiki](/systems-and-emulators/supported-game-systems.md).
{% endhint %}

{% hint style="warning" %}
BIOS files are copyrighted and are therefore not included with Retrobat.&#x20;

The team can not legally distribute them, so you will need to dump them from the original hardware.
{% endhint %}


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