How To Make The FN Function Key Work On The R35S/R36S

The function button on the R36S and its predecessor R35S handheld emulator consoles not working, or not being able to be assigned is a common issue with these devices. Luckily, this key can actually be rather easily assigned as a shortcut or a hotkey after some software tweaks. Let’s get to the fix.

What Does The “FN” Button On The R35S/R36S Do?

This is definitely one of the questions I’m getting asked the most when it comes to these handhelds, and the answer is: nothing, at least not by default.

The function button labeled “FN”, which is positioned in the middle of the R36S or the R35S handheld between the start and select buttons, in the default firmware configuration isn’t visible to the ArkOS system kernel, and as of the time of writing this article does not show up as an accessible input in the /dev/input/eventX system directory.

So, why doesn’t it work properly? Well, as the R35S and the R36S are effectively clones of the POWKIDDY RGB20S handheld, there is a slight suspicion that when copying over the feature set, the unassigned FN button was simply overlooked and not properly addressed within the device’s firmware. As you might have guessed, this was a big problem on the RGB20S too. But anyway, let’s get to the quick fix.

The FN button not being visible to the hardware can be fixed by modifying some files on the microSD card holding the console’s system, and then restarting the handheld. Read on to see how exactly to do this!

Make The FN Function Key Assignable (R35S & R36S Handhelds)

Using the files from this GitHub repository, you can rather easily make the function button assignable in under a few minutes. Huge props to norucus / AeolusUX for this fix! And here is how to do it on your device:

Note: Before modifying your system files, it’s best to backup the content of your system microSD card and save it somewhere on your PC in case something goes wrong.

After downloading all the files from the linked repository and connecting your microSD card containing your console’s system to your PC, simply copy all the files from the repository over onto your handheld’s main boot partition.

Make sure that all the files were copied and replaced, and then after putting the microSD card back into the handheld, turn the device back on. After you do that, you will be able to use the button as a custom hotkey in Retroarch or Emulationstation. That’s it! For more info, refer to the original Reddit thread here.

Now that this button is visible to the OS, you’ll most likely want to map it as a hotkey in the emulators you use. Remember that you will have to map it separately in every emulator (EmulationStation, Retroarch, PPSSPP, and so on). The button mapping settings will be accessible from the input/hotkey settings menus.

Note that this fix might possibly be integrated into ArkOS at some point, so if you don’t want to go through the process of setting it up, you can also wait until it’s included in one of the future updates. That’s all for now!

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