Where Does muOS Store ROMs and Saves?
muOS keeps system data on the SD card with ROMs, saves, and themes in fixed folders. Back up the card before updating the system image.
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muOS runs entirely from the SD card on supported handhelds. The card holds the system, the ROM library, per-game saves and states, scraped media, and themes in a fixed layout. Pull the card and the device is an empty shell.
That makes the card the backup unit: image it or copy the data folders before any system update. Save states break across core updates while battery-backed SRAM saves survive, so prefer in-game saves for long RPGs. Keep a second card with a known-good build for rescue days and experiments.
Where muOS stores this, by platform
/mnt/mmc/MUOS/
Whole system on SD: ROMs, saves, states, media, themes. Back up the card before updates. Prefer in-game saves over states across core upgrades.
Frequently asked questions
How do I update muOS safely?
Flash the new image to the card with the device off, keeping a backup of the ROMs and saves folders first. Themes and collection settings may need reapplying after major releases. Never update from a low battery; a brownout mid-write eats cards.
Where do ROMs and saves go?
ROMs go in the per-system ROM folders and saves beside them in the saves tree, with states in their own folder. Point scraped art at the matching names so the gallery fills in. Keep BIOS files in the BIOS folder for systems that need them.
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