How to Hardcode 6-Button Mapping for 8BitDo Arcade Stick (Bluetooth XInput, Supergun Setup) on BlueRetro?

[morgan-jy]

Hi,

I am trying to hardcode the button mapping for the 8BitDo Arcade Stick (Bluetooth mode, Xinput profile) using BlueRetro firmware.

My goal is to use 6 action buttons properly and to rearrange their layout according to my needs.

However, I am not sure exactly which source files I should modify for this:
• Should I change parallel_1p.c, adapter.c, hid_parser.c, or other files?
• For the 8BitDo Arcade Stick connected over Bluetooth in Xinput mode, do I also need to manually add the VID/PID into the HID parser?
• Or is there a better (or more correct) way to modify mappings when dealing with Generic HID devices?

It seems the VID/PID might differ depending on the connection type (Bluetooth vs. Xinput), so I want to be very careful before making changes.

Here is my current system flow:
1. 8BitDo Arcade Stick is paired via Bluetooth (Xinput mode).
2. BlueRetro is connected to a Supergun system through the Parallel 1P interface.
3. OTA config mapping did not allow enough remapping, so now I am preparing to hardcode manually.
4. I am stuck at the point of deciding which source file(s) to modify for proper button mapping and layout adjustment.

I am very new to hardcoding firmware like this.
I just want to receive some advice or a hint on which direction I should start with.

Thank you very much for your help!

---

Adding update.
After flashing the latest firmware (v25.04), all six buttons are now recognized correctly on the Parallel 1P interface with my Supergun setup.

Now I only need to rearrange the button layout.

I’m still seeking advice on which source files I should modify to remap the button layout properly.

Thank you!

[morgan-jy]

[morgan-jy]

After some investigation, I noticed that all six action buttons are recognized correctly in the current v25.04 firmware using the Parallel 1P interface.

Based on analyzing the parallel_1p.c source code, it seems the six active buttons correspond to Generic indexes 16, 17, 18, 19, 24, and 28.

Since the button inputs are already functioning, I believe it is possible to simply rearrange the button mappings by editing the para_1p_btns_mask[] array, without needing to modify HID parsing or adapter logic.

Before proceeding, I would like to confirm:
• Is it safe to just adjust para_1p_btns_mask[] for my custom button layout?
• Or is there anything else I should be careful about when remapping at the Parallel 1P level?

Thank you for your guidance!

---

BlueRetro/main/adapter/wired/parallel_1p.c

static DRAM_ATTR const uint32_t para_1p_btns_mask[32] = {
0, 0, 0, 0,
0, 0, 0, 0,
BIT(P1_LD_LEFT), BIT(P1_LD_RIGHT), BIT(P1_LD_DOWN), BIT(P1_LD_UP),
0, 0, 0, 0,
BIT(P1_RB_LEFT), BIT(P1_RB_RIGHT), BIT(P1_RB_DOWN), BIT(P1_RB_UP),
BIT(P1_MM - 32) | 0xF0000000, BIT(P1_MS), BIT(P1_MT), 0,
BIT(P1_LM), BIT(P1_LM), 0, 0,
BIT(P1_RM - 32) | 0xF0000000, BIT(P1_RM - 32) | 0xF0000000, 0, 0,

[darthcloud]

Why not using the mapping feature from the config interface?
https://github.com/darthcloud/BlueRetro/wiki/BlueRetro-BLE-Web-Config-User-Manual#24---mapping-config

[morgan-jy]

@darthcloud

Thank you for your response.

I viewed reading in the documentation(or community) that Paralle mode only allows hardcoded mapping,
so i tried that approach.
Howerver, hardcoding is not easy for me. 😢

I initially tried using the mapping feature mentioned above, but it didn’t work properly.

Could you please review the method I attempted below and let me know if I’m on the right track?

Current setup & goal
I’m trying to remap six buttons to my preferred layout.

Connection path:
8Bitdo Arcade Stick (XInput mode) → Bluetooth → BlueRetro SNK → Supergun

Firmware used:
BlueRetro_hw1_parallel_1p.bin (v25.04)

Steps I followed:
1. BlueRetro Advance Config → Global Config → System → Set Parallel_1P_PP
2. Mapping Config
• Src label → 8bitdo SN30/SF30 (arcade stick not listed, so chose SN30)
• Dst label → Neogeo (Parallel 1P)
3. Remap dest in Mapping Config

I tried changing the “Dest” fields to my desired layout and tested with various settings, but none of the buttons worked as expected.
Also, it was difficult to figure out the correct mapping format or rules.

⸻

Could you confirm if the steps I took are correct?
And could you also provide guidance on how to properly change the mapping?

For reference, my target button layout is as follows:

[morgan-jy]

It' cleared.
i use mapping feature.
Thanks