MAME BIOS and parent diagnostics / 2026-07-30

Read MAME's BIOS and parent search order before moving files on Android

Turn a missing-file message into an exact dependency and location check instead of copying BIOS and parent files into every game archive.

10 minute dependency guideOfficial MAME 0.288 stable concepts; Android ports may expose rompath through a picker or app-private directory

Read MAME's BIOS and parent search order before moving files on Android

Read the locations MAME says it tried. For a system ROM, current MAME searches the selected system, its parent when applicable, and its BIOS system in every configured rompath. Keep each authorized set under its own short name, audit the selected game, and repair the named dependency at the rompath level; do not merge unknown BIOS bytes into the child ZIP.

Do this in order

  1. 01

    Record the exact MAME or core build, selected game short name, configured rompath, set style, and the first complete missing-file message.

  2. 02

    Use that build's list information to identify the selected system, parent, BIOS system, device sets, and any CHD dependency.

  3. 03

    Check every configured rompath for archives or folders named after the selected system, parent, BIOS, and named devices; do not assume the game folder is the only search location.

  4. 04

    Run a targeted `-verifyroms shortname` audit in standalone MAME, or capture the equivalent audit from the Android port.

  5. 05

    Return to your own dump or authorized source for the exact build and replace only the dependency proven wrong or absent.

  6. 06

    Re-run the audit, then launch once with default configuration and preserve the passing build, short name, source, and audit date.

Decision and diagnostic table

Missing layerExpected identitySafe next check
Selected systemGame short nameArchive/folder and targeted audit
Parent systemReported parent short nameSet style and parent presence
BIOS systemReported BIOS short nameBuild-specific list and checksum
CHDExpected disk name and digestFolder layout and parent CHD

The error is a search trace

MAME's file-search documentation explains that a system ROM can be found under the selected system, its parent, or its corresponding BIOS system. The failure message lists the places tried, which is stronger evidence than a guessed Android folder.

Android wrappers may hide the upstream path syntax behind a Storage Access Framework grant or private library. Verify what the port actually exposes before applying desktop instructions.

BIOS choice is not BIOS integrity

A BIOS selection chooses among firmware variants already defined for a system or device. It does not create a missing BIOS archive and it cannot make bytes from another MAME generation match current hashes.

Keep BIOS and device sets independently identifiable. Copying their contents into every child archive destroys provenance and can make a later audit harder to interpret.

CHD follows a related but separate path

CHDs represent mass-storage media and should not be placed inside ZIP or 7-Zip archives. A clone can also use a delta CHD that requires the matching parent CHD.

Pass the ROM audit first, then confirm CHD name, digest, folder, and parent relationship. A valid CHD cannot replace missing system, parent, BIOS, or device ROM data.

First-party sources

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