Creating a custom X68000 boot logo splash screen

The Sharp X68000 has a visual character that begins before a game, demo or utility reaches its title screen. The dark display, crisp Japanese system text and distinctive startup sequence make the machine feel like a dedicated appliance rather than a generic home computer. Replacing that first image with a personal boot logo can make a restored tower, development system or exhibition machine feel genuinely yours.

A custom splash screen does not have to mean rewriting the X68000’s ROM. In most cases, the safer approach is a small boot-disk program that switches to a suitable graphics mode, loads an image, displays it for a few seconds and then starts Human68k or another application. This keeps the original firmware intact and makes the change reversible.

The project suits several kinds of X68000 owner. A collector may want a historically sympathetic Sharp-style mark, a game developer may display a studio logo, and a repairer may use a diagnostic screen to identify a particular machine. It can also provide a polished front end for a Compact, XVI or tower connected to modern storage.

Australia adds a few practical considerations. Japanese machines are commonly imported through eBay, Yahoo Auctions intermediaries and specialist retro sellers, while local availability of compatible 15 kHz monitors and keyboards can vary between Melbourne, Sydney, Brisbane and regional areas. A careful software-first modification avoids unnecessary work on the power supply or video hardware.

Approach	What it changes	Difficulty	Best use	Main risk
Boot-disk splash program	Files on a floppy, SCSI disk or CompactFlash setup	Low	Reversible personal branding	Incorrect startup commands
Custom loader	A program that displays an image and launches software	Medium	Dedicated gaming or demo systems	Memory and mode conflicts
ROM or IPL modification	Firmware or early boot behaviour	High	Preservation research	Difficult recovery and hardware damage
Animated startup demo	Graphics, music and timed effects	Medium to high	Exhibitions and showcases	Slow loading or unstable drivers

Decide where the image belongs

The first decision is whether the logo should appear before Human68k, during the operating system startup, or immediately before a chosen application. The built-in IPL and ROM routines are part of the machine’s low-level startup process, so changing them is substantially more invasive than adding a program to a boot disk. A file-based splash is usually the sensible option for an enthusiast machine that should remain reliable.

A startup program can be launched through the disk’s command files, commonly by placing it in the expected boot sequence and then handing control to a shell, menu or game launcher. Exact filenames and command syntax depend on the operating environment, disk image and version of Human68k. Test the program from a command prompt first; a splash that works manually but fails during boot is often suffering from a path, drive-letter or memory-resident utility conflict.

Keep an untouched system disk or disk image as the recovery baseline. Work on a copy stored on a modern computer, and retain a second copy on removable media. X68000 floppy disks are vulnerable to age, mould, magnetic damage and weak drive mechanisms, so treating the original as the only backup is risky. If the machine uses a SCSI2SD, BlueSCSI-style device or CompactFlash solution, make an image before editing its startup files.

There is also value in documenting the original behaviour. Photograph the startup screen, record the display mode and note the commands that run. A preservation-minded splash can then be removed later without obscuring the machine’s historical configuration.

Prepare artwork for the X68000 display

A logo designed for a modern 16:9 monitor rarely looks right on an X68000. Start with the target resolution and colour depth of the mode you intend to use. Common X68000 graphics modes are based around 15 kHz output and can use square-looking pixel arrangements that appear stretched on some LCD converters. A simple, high-contrast mark with generous margins generally survives the transition better than fine typography.

Keep the original artwork in a lossless format such as PNG on your development computer, then convert it into the format expected by the loader. Depending on the utility, that may be a raw planar bitmap, a palette-based image or a tool-specific asset. Do not assume that a file extension tells you enough: two programs may both use a similar name while expecting different bit order, palette layout or header information.

Limit the palette deliberately. The X68000’s graphics hardware is capable of attractive colour work, but a startup logo is easier to reproduce when its colours are chosen from a known palette. Test bright reds, dark blues and near-black shades on the actual monitor, because CRT phosphors and video converters can make adjacent colours merge. A logo intended for a Sony PVM may need different contrast from one shown through an OSSC or a generic HDMI scaler.

Design a monochrome fallback as well. It can be used for troubleshooting, printed in documentation or displayed when the preferred graphics utility is unavailable. Avoid tiny Japanese or English text unless the screen remains visible for long enough to read it. A short machine identifier, model name and year are more useful than a dense credits panel.

Build the loader without altering firmware

A minimal loader has four jobs: initialise the graphics mode, load the image and palette, wait for a suitable interval, and transfer control to the next command or application. The exact implementation can be written in C, assembly or an existing X68000 development environment. For a first attempt, adapting a known image viewer or screen utility is often less error-prone than writing every graphics routine from the beginning.

The program should fail cleanly. If the image file is missing, it should print a readable error and return to the command line rather than leaving the display blank. If the requested mode cannot be initialised, retain the original text display where possible. This matters when a disk is moved between an X68000 Pro, XVI and Compact, or when a modern storage adapter presents a different directory structure.

An Arduino keyboard project can be useful during development because it provides a practical way to enter commands when an original keyboard is unavailable. The USB keyboard adapter guide is relevant when setting up a test bench, especially for owners who would rather not risk a scarce Japanese keyboard beside an open machine.

Place the image and executable in a clearly named directory rather than scattering files through the root of the boot disk. Use short filenames compatible with the target Human68k environment, and avoid depending on a drive letter that may change when the system boots from floppy, SCSI or a flash-backed device. A small configuration file can hold the display duration, image path and optional launch command, making later changes less invasive.

Test it with real hardware and safe recovery

Begin testing with the X68000 connected to a display known to accept its signal. Many Japanese X68000 machines output 15 kHz RGB, and not every modern television or computer monitor accepts that timing. An Australian PAL CRT may be suitable, but its connector wiring and sync expectations must be checked rather than assumed. Some owners use a Japanese RGB monitor, an arcade-compatible display or a scaler with an appropriate low-resolution input.

Do not confuse a display problem with a broken loader. First run the program while keeping the original command line available. Then test the image, palette, timing and return path separately. A screen that becomes black after the logo may simply be waiting for a key, attempting to launch a missing program or switching to a mode that the converter cannot display.

Power work deserves separate caution. Australian mains supply is nominally 230 volts at 50 Hz, while many imported X68000 power supplies contain ageing capacitors and components designed for the Japanese market. A splash-screen project does not require opening the mains section. If the machine needs electrical repair, use a qualified technician and observe applicable Australian electrical safety requirements; software customisation is a poor reason to take risks around an exposed power supply.

Hardware expansion experiments can also affect boot testing. If a digital I/O card, accelerator or storage board changes memory mapping or startup behaviour, remove variables one at a time. The notes on using the expansion bus for I/O provide useful context for owners whose system includes custom hardware. Test the logo on a standard configuration before adding peripherals back into the chain.

A recovery disk should be within reach during every test. If the automatic sequence fails, interrupt it with the keyboard, boot from the clean device or connect the storage media to a modern computer and restore the saved image. Never overwrite the only copy of a working boot disk while experimenting with startup commands.

Make the splash part of a lasting setup

Once the screen works, decide whether it is a personal signature or part of a broader front end. A quiet three-second logo is suitable for everyday use, while a longer animation may be appropriate at a club meeting or museum display. For a game library, the splash can lead to a menu with categories, language notes and hardware requirements. Keep a direct route to the command line so the presentation layer never becomes a barrier to maintenance.

For an Australian collection, include practical identification in the artwork or documentation: the model, storage arrangement, video adapter and restoration date. This is helpful when a system moves between a home office in Adelaide and a public event in Perth, or when several nearly identical towers are stored together. It also creates a useful record if the machine is sold through a local retro-computing group.

Consider copyright and presentation rights when the logo uses commercial artwork. A self-created mark or a logo for a project is straightforward, while copying a publisher’s branding for a public event may create avoidable issues. Australian Consumer Law can be relevant when buying or selling used equipment, but it does not turn an unlicensed graphic into permissible software content. Keep private experimentation separate from redistributed disk images.

Distribution should include a readme, the original asset, the converted image, build notes and a clean boot configuration. Add checksums for important files and describe the target graphics mode. If the project is shared online, state whether it expects a floppy, SCSI hard disk, CompactFlash adapter or emulator. Clear packaging helps other enthusiasts reproduce the result without guessing at the environment.

A custom X68000 boot logo splash screen is most successful when it adds character without compromising recoverability. The original ROM remains preserved, the startup files are backed up, and the artwork respects the limits of the hardware. That balance reflects the broader retrocomputing ideal: improve the experience while keeping the machine’s history accessible.

Build the project in small stages, beginning with a static image and a manual launch. Record the display mode, storage setup and loader version, then automate the startup only after each part has been verified. Share the finished files with their source artwork and recovery instructions so another X68000 owner can learn from the work, adapt the design and keep this unusual Japanese platform active in Australia and beyond.