List of third-party OPK applications

This article lists third-party OPK-format applications built for the FunKey S. Freely downloadable from this page, these applications allow users to add additional functionalities to their devices. Once downloaded, these files are placed in any folder at the root of the device's file system, with the Applications, Emulators, and Native games folders available by default for file management. The application can subsequently be accessed from the Gmenu2x launcher, where it is sorted automatically by its type: application, emulator, or game. As the device's Instant Action autosave feature is implemented on a program-by-program basis, users must remember to manually save their progress in any third-party program that hasn't implemented Instant Action. Also note that while many devices use OPK as an application format, only OPK applications compiled specifically for the FunKey S are compatible with it.

Should you wish to build or modify OPK applications yourself, you may download a version of SquashFS configured for editing OPK applications on Windows here. After extracting the SquashFS folder from its ZIP archive, add the OPK file that you wish to edit to the folder and double-click the ''1. EXTRACT_OPK.bat'' file. This will create a folder called squashfs-root, containing files for the application's configuration settings, icon image, and binary data. Unless you have prior experience configuring OPK applications, however, it is recommended that you only modify the icon file, a 32-pixel square PNG format image file that represents the application in Gmenu2x. In doing so, ensure that the replacement icon file is also a 32-pixel square image, in PNG format, and named exactly as the original file was (icon.png is replaced with icon.png). Once you have finished modifying the application, return to the SquashFS folder and double-click the ''2. MAKE_OPK.bat file, which will apply your modifications to the submitted OPK'' file. After several windows pop up and disappear, your application will be modified and ready to be returned to your FunKey S. Note that if there are multiple applications that you wish to modify, you must do so one at a time. For additional instructions on how to use SquashFS to modify or build OPK applications, it is recommended that you join the FunKey Community Discord Server.

Applications
The following applications are any programs for the FunKey S that are neither emulators nor games. Alongside each application is listed a general description of it.

Emulators
The emulators listed in this section add to the capabilities of the FunKey S by enabling improved emulation of several supported systems and general emulation of several unsupported systems. As a means of helping users choose which emulators to use, especially for cases in which there are multiple options, the following table lists currently unsupported systems on the left with the best emulators currently available for them on the right:



Should a system not be listed above, it is either that it is already officially emulated by the FunKey S or that its emulation has insufficient functionality for use by a general audience. To illustrate cases of the latter, each emulator is rated from low to high for both overall emulation accuracy and speed. In addition to the emulators listed on this page, should you wish to emulate BBC Micro, CHIP-8, Sharp X1 Turbo, Sierra AGI, or ZX Spectrum, meta-emulation via the Game Boy Advance is an additional option for third-party emulation. Should one of the emulators listed on that page be incompatible with the default gpSP emulator, however, the SDL Retro mGBA core or the standalone VBA Next emulator would be needed to use the meta-emulator.

If one or more required BIOS files are listed alongside an emulator, ensure that those files are named and located as that emulator expects to improve emulation results. For all SDL Retro cores, the expected BIOS file location is /mnt/FunKey/.sdlretro/system. For PCFXEmu, the expected file location is /mnt/FunKey/.pcfxemu. For SMS Plus GX, the expected file location is /mnt/FunKey/.smsplus/bios. As PCSX ReARMed Ultimate simply replaces the default PCSX ReARMed core, the BIOS file for it goes in the regular /mnt/PS1/bios file location. Additionally, to improve the CPS2 emulation of FinalBurn Alpha, this configuration file should be placed in the /mnt/FunKey/.sdlretro/cfg location of the FunKey S file system. If you don't see the .sdlretro, .pcfxemu, or .smsplus folders, your computer's Unix-based operating system is hiding hidden folders.

Games
The following applications are freeware games that have either been ported to or natively developed for the FunKey S. To facilitate list navigation and game selection, alongside each game is listed its genre. To play the OPK ports of commercial games, one or more additional files containing necessary copyrighted assets must be provided by the user from their own legally acquired copy of the game. The data files of such games should be grouped together in a folder located at that game's listed file location. Games requiring several of a specified file type to run have an asterisk placed after the applicable file type(s).

Make note of the following information for the following games:
 * While Doom, Doom II, and Final Doom only require a single WAD file each, add-on WAD files also can be used
 * While Quake only requires its PAK0.PAK file to launch, to access the full game, the PAK1.PAK file is also required
 * Due to the FunKey-OS V2.3.0 update, VVVVVV is currently non-functional

If you don't see the .local folder, or the .cannonball or .ecwolf folders disappear upon creation, your computer's Unix-based operating system is hiding hidden folders.