Firmware & Files (ROMEMUL)

Table of contents
  1. ROMEMUL volume
    1. Common files you may see
  2. Safe eject (important)
  3. FAT12 notes
    1. Copying files (macOS / Windows / Linux)
  4. Magic file and folder names
  5. Firmware updates

ROMEMUL volume

The ROM Emulator exposes its on-board flash as a USB mass-storage volume (FAT12), typically named ROMEMUL.

This is the same core workflow used across SidecarTridge ROM-emulation products (e.g., TOS emulator and Kickstart emulator):

  • When powered from USB-C, the device starts in Volume (ROMEMUL) mode so you can manage files from a computer.
  • You copy ROM images and configuration files onto the volume.

Common files you may see

Depending on firmware/features, you will typically find some of these files in the root of ROMEMUL:

  • INDEX.HTM — opens the device documentation website.
  • INFO.TXT — shows installed firmware version/date, board details, flash size, etc.
  • CONFIG.TXT — advanced configuration (timing/speed tuning, and other firmware options).
  • DEFAULT.TXT — name of the default active ROM image (when supported).
  • RESCUE.TXT — name of the rescue ROM image (when supported).
  • Tool folders (product-specific), for example:
    • AMIGA/ (Kickstart: SWITCHER app)
    • SWITCHER.TOS (TOS: Atari-side switching tool)

You may also see hidden metadata files created by your operating system (names starting with .). These are not used by the ROM Emulator.

Safe eject (important)

As a rule of thumb, ALWAYS eject/unmount the ROMEMUL volume after making changes. This ensures the FAT metadata is flushed correctly and the emulator re-indexes images/config reliably.

FAT12 notes

  • The ROMEMUL volume uses FAT12 and typically a 4 KB cluster size.
  • File sizes may appear rounded up (4 KB steps). This is expected.

Copying files (macOS / Windows / Linux)

  • You can drag & drop files in most cases.
  • On macOS, Finder may create temporary hidden files; if you run into issues, prefer copying from Terminal:
cp -R /path/to/ROM\ Images/* /Volumes/ROMEMUL/

On Linux, the mount point varies by distro:

cp -R /path/to/ROM\ Images/* /media/username/ROMEMUL/

Magic file and folder names

Some SidecarTridge ROM-emulation firmwares support “magic” file/folder names that trigger actions when the ROMEMUL volume is ejected.

Common examples:

  • REBOOT — after eject, the device attempts to mount the volume again.
  • RESET — after eject, the device enters BOOTSEL mode and exposes a RPI-RP2 or RP2350 volume so you can flash firmware.

Magic files/folders are typically deleted after the action is triggered.

Firmware updates

The ROM Emulator ships with firmware installed, but you may want to update it.

  • The installed firmware version can be checked in INFO.TXT.
  • Firmware update procedures are product/board specific.
  • If your firmware supports the RESET magic name, it can be used to enter BOOTSEL mode.

Some firmware updates (especially major upgrades) may erase stored images. Back up your ROMEMUL contents before updating.

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