Joycons Android + HOS pairing

Dump HOS system partition, retrieve the file "/save/8000000000000050".

Open 8000000000000050 in a hex editor, find the string "Joy-Con"

You should see two entries within the file, for your left and right joycon, and whatever other controllers you've synced I guess.

The entries should look like this: https://lewd.pics/f/c9ec2b60/2019-08-11--1565575206_954x1147_scrot.png

Under those strings, you should see a block of bytes like "25 08 XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX 01"

The 16 bytes between "25 08" and "01" are your joycon pairing keys. Write both of them down somewhere.


You need to get your console's Bluetooth Mac address as well. That's in your prodinfo at 0x220, the first six bytes.


Now open up your Android userdata partition and go to /misc/bluedroid/. Find the file "bt_config.conf".

If you've paired your joycons in android before, there should already be two entries for them.

In those entries, find the "LinkKey" setting. Stick the keys you obtained earlier here, instead of what was already there. Lowercase, no spaces, exactly as what was already there.

You can also probably change the "[Adapter]" entry's address to your HOS mac address, but I don't think it really matters.


After all of that, you need to change Android's Bluetooth address to the one HOS uses. You can do that easiest by opening your android boot partition (can be dumped in TWRP), and searching for the string of bytes AC1F00A35643 (This is the default bluetooth address in little endian; 43:56:a3:00:1f:ac)

You'll find two results. Replace these with HOS's bluetooth mac address you retrieved earlier, little-endian.

Flash your boot partition back.


If you did everything right then your joycons should work in HOS and Android without requiring a repair every time you swap. Horray!