8BitDo Retro 108 · Karabiner-Elements

Retro 108 MacMap

Twenty-two rules that make the Retro 108 behave like a Mac keyboard — Windows-layout modifiers swapped, the Xbox Game Bar F-row turned into macOS screenshot and recording shortcuts, the padlock key wired to Lock Screen, and the keys macOS ignores given jobs.

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Open the rule picker

Every rule with a switch on it. Turn off what you do not want, change the ones whose output is a matter of taste, and give any of those a second action on hold. Runs entirely in your browser.

What the rule set covers

Group	Rules	What it does
Screenshots	5	The Game Bar F-row, rebuilt as macOS capture shortcuts
Padlock key	1	Lock Screen, via a simultaneous rule
Navigation	3	Terminal-compatible line movement and forward delete
Dead keys	3	Scroll Lock, Pause and Insert sent as F14–F16
Silenced	5	F5–F8 and F12 disabled so macOS cannot claim them
Num Lock	1	Starts the screensaver
Modifier swaps	4	Windows layout to Mac layout

Every rule carries device_unless is_built_in_keyboard, so a laptop keyboard is left alone.

Three things to get right first

1. FN lock has to be engaged on the board. Four of the capture rules depend on it, and without it the F-row sends media keys instead.
2. Set the Globe key to do nothing in System Settings → Keyboard. Its default action fires before Karabiner sees the key.
3. Leave "Use F1, F2, etc. as standard function keys" OFF. This rule set disables those keys inside Karabiner, so macOS never sees them anyway.

Neither of those is the Modifier Keys panel. The modifier swaps live entirely in the JSON.

The files

• builder.html All 22 rules with a switch on each, assembling the file as you go.
• README Setup and the keymap.
• NOTES The lab notebook: the reasoning, the traps, and the deliberate non-fixes.
• INDEX A map of the whole repository.
• retro108-macmap.json The rule set itself. Twenty-two manipulators.
• Retro-108-Mechanical-Keyboard.pdf 8BitDo's booklet, for the layout and the FN combinations.

The part most people miss