gen1recomp/docs/guides/launch-options.md

Launch options

By default the app opens the launcher so you can pick a game. Launch options skip it and start one game directly, which is what you want for a one-click entry: a desktop shortcut per game, a Steam entry, or a handheld frontend.

Option	Effect
--game=red	boot Red, skipping the launcher (blue, yellow, gold, silver and crystal too, or just r / b / y / g / s / c)
--cart=id	boot the installed custom cart with that id
--slot=2	load that save slot; takes a slot number or a slot id
--launcher	open the launcher anyway, so you can edit a shortcut you already made
--no-sync	skip the save sync a linked device otherwise runs before the game boots (POKEPORT_LAUNCH_SYNC=0)
--update	check for a release first, and restart once into it if one is ready (POKEPORT_LAUNCH_UPDATE=1; -update works too)
--update-mods	run the MODS tab's Update all (mods and custom carts) without the confirm, then boot; stays on the launcher if an update fails (POKEPORT_LAUNCH_UPDATE_MODS=1; --updatemods works too)

If this device is linked for save sync, a shortcut syncs before it boots so CONTINUE never loads a save another device has already moved past. The screen shows what it is doing and any button skips straight into the game; a sync conflict opens the launcher so you can pick a copy rather than booting over one.

URL launch (Android and iOS)

Android and iOS accept the same launch request as a URL:

gen1recomp++://launch?game=red

URL	Effect
gen1recomp++://launch?game=red	boot Red directly
gen1recomp++://launch?game=red&cart=my_cart	boot the installed custom cart my_cart
gen1recomp++://launch?game=red&slot=2	boot Red and select save slot 2
gen1recomp++://launch?game=red&launcher=1	open the launcher on Red instead
gen1recomp++://launch?game=red&sync=0	skip save sync
gen1recomp++://launch?game=red&update=1	check for an update before booting
gen1recomp++://launch?game=red&update_mods=1	update mods and carts before booting

The game value accepts the same full names and aliases as --game. Boolean parameters accept 1/0, true/false, yes/no, and on/off. Percent-encode values that contain characters reserved by URLs; the app decodes query values before applying them. cart is the installed cart id shown in the Custom Carts screen. Unknown parameters are ignored, and an invalid game or cart falls back to the launcher.

To test a link on Android, use the installed application package:

adb shell am start -a android.intent.action.VIEW \
  -d 'gen1recomp++://launch?game=red' \
  com.theboisclub.pokemonred

To test a link in the iOS Simulator:

xcrun simctl openurl booted 'gen1recomp++://launch?game=red'

On a physical iPhone or iPad, open the URL from another app that can hand off custom URLs, such as Notes, Messages, or Safari.