Powkiddy X55

Overview

Hardware

SoC	CPU	GPU
Rockchip RK3566	ARM Cortex-A55 (Quad-core) @ 1.8 GHz	Mali G52

Display	RAM	eMMC	Connectivity
5.5-inch 1280*720	2 GB LPDDR4X	8 GB (except early revisions)	2.4/5 GHz WiFi + BT (8821CS)

Software

Kernel	GPU drivers	Compositor	Interface
Mainline Linux	libmali (GLES 3.2) & Panfrost (GL 3.1/GLES 3.1)	Sway	Emulation Station

Tweaks

In Emulationstation system settings you find an overclock setting and undervolt options. The overlock option enables 2 GHz operation. While there are 3 levels of undervolting, where L1 is the least undervolt and L3 is the most undervolt. Undervolting can help performance in higher end emulators such as PPSSPP and Yabasanshiro standalone, due to less thermal throttling. As well as less battery drain on lower end emulators.

Obviously it can't be guaranteed that all specimens can undervolt and hence you may end up with a non-booting or unstable system. If this is occurs, the undervolting can be reversed by:

1. Inserting the OS SD card into a PC.
2. Open ROCKNIX partition, and go to the extlinux folder.
3. Open extlinux.conf text file.
4. Completely remove the line that starts with FDTOVERLAYS.
5. Now your device will boot with stock voltages.

Features

Feature	Notes
Storage	ROCKNIX can be installed to the emmc or run from an SD Card, and an second SD card can be used to store games
Wifi	Can be turned on in Emulation Station under Main Menu > Network Settings
Bluetooth	Supports bluetooth audio and controllers

Controls

RetroArch Hotkeys

Button Combo	Action
SELECT+START (x2)	Quit Game
SELECT+R1	Save State
SELECT+L1	Load State
SELECT+X(NORTH)	Open RA Menu
SELECT+Y(WEST)	Show FPS
SELECT+R2	Fast-Forward

Notes:

• By default ROCKNIX will detect your controller and configure RetroArch hotkeys automatically. This is controlled by the "AUTOCONFIGURE RETROARCH HOTKEYS" option in the Settings > Controller & Bluetooth menu. While the option is enabled, RetroArch hotkeys will be overwritten by the above defaults each time RetroArch is launched. If this behavior is not desired that option can be disabled and your user-defined RetroArch hotkeys will be used instead.

Mednafen Hotkeys

Button Combo	Action
SELECT+START (hold for 2sec)	Quit Game
SELECT+R1	Save State
SELECT+L1 (hold for 2sec)	Load State
SELECT+Y(WEST)	Show FPS
SELECT+R2	Fast-Forward
START+L1	Select disc
START+R1	Eject/Insert disc
START+D-Pad Left	Decrease save slot by 1
START+D-Pad Right	Increase save slot by 1
START+L2	Configure buttons on virtual port 1
START+R2	Insert coin

Notes:

• By default ROCKNIX will expand the configuration file according to the first controller mednafen finds. This only happens when the config file doesn't exist (meaning the first time or if you manually delete it). After the initial expansion you are free to customize the controls.

Mupen64Plus-SA (Nintendo 64)

Button Combo	Action
START	Start
B(SOUTH)	A
Y(WEST)	B
Right Analog Up	C Up
Right Analog Down	C Down
Right Analog Left	C Left
Right Analog Right	C Right
L2	Z
L1	L
R1	R
SELECT+START	Quit Game
SELECT+R1	Save State
SELECT+L1	Load State
SELECT+Y(WEST)	Take Screenshot
SELECT+B(SOUTH)	Reset Game

Notes:

• Z and L button assignment can be changed directly in EmulationStation
  • Highlight the game and press X(NORTH)
  • Select ADVANCED GAME OPTIONS
  • Set EMULATOR to MUPEN64PLUSSA
  • Then change INPUT ONFIGURATION
    • Default: L1 = L, L2 = Z
    • Z & L SWAP: L1 = Z, L2 = L
• You can also create your own custom controller configuration and add it to /storage/.configs/game/configs/mupen64plussa. Then update INPUT CONFIGURATION to CUSTOM following the same steps as above.

PPSSPP-SA (PSP)

Button Combo	Action
START	Start
SELECT	Select
A(EAST)	Circle
B(SOUTH)	Cross
X(NORTH)	Triangle
Y(WEST)	Square
L1	L
R1	R
R2	Save State
L2	Load State
L3	Open Menu

Hypseus-singe (Daphne)

Button Combo	Action
SELECT+START	Quit Game
SELECT	Coin
START	Start
B(SOUTH)	Button 1
A(EAST)	Button 2
X(NORTH)	Button 3

Notes:

• To add/change mapping you can edit /storage/.config/game/configs/hypseus/hypinput.ini under [KEYBOARD] section by changing third number for a function from 0 (disabled) to a corresponding joystick value. You can identify joystick values by running jstest /dev/input/js0 over ssh.

• For example the following would assign quit to L1 and pause to R1

  [KEYBOARD]
  KEY_QUIT = SDLK_ESCAPE 0 5
  KEY_PAUSE = SDLK_p 0 6
  

Global Hotkeys

Button Combo	Action
SELECT+Vol +	Brightness Up
SELECT+Vol -	Brightness Down
START+Vol +	Battery Status
START+Vol -	WIFI Toggle

Emulators

• Platform Documentation (RK3566)

Notes

Installation

Download the latest RK3566-X55 version of ROCKNIX from the button below and follow the instructions listed on the Install page.

Screen Calibration

The Powkiddy X55 screen is miscalibrated from the factory. While there's no universal fix (yet) this issue can greatly be mitigated by using a Retroarch Shader. Instructions for doing so are listed below:

1. Start a game
2. Open the "Quick Menu" in Retroarch by pressing both joysticks
3. Navigate to "Shaders"
4. Turn "Video Shader" to "ON"
5. Navigate to "Load Preset"
6. Select "Misc" -> "Image Adjustment"
7. Go to "Shader Parameters" and change the following parameters:
8. Target Gamma -> 2.40
9. Monitor Gamma 2.00
10. Saturation -> 1.50
11. Contrast -> 1.15
12. Black Level -> -0.10
13. Navigate back to the shader menu and pick "Save Preset"
14. Select Either:
15. "Save Global Preset" to have this as the default for all Retroarch cores
16. "Save Core Preset" to have this as the default for a specific system (e.g all PSX games)
17. "Save Content Preset" to have this as the default for a specific directory (e.g all roms in a "RPG" directory)
18. "Save Game Preset" to have this as the default for the specific game that you're running

The settings at 7 are just a proposal, you might want to experiment a bit to get something that matches your preferences but they should serve as a great starting point.

As a bonus, adjust the "Horizontal Overscan %" and "Vertical Overscan %" settings to deal with e.g PSX games that have black borders (such as Crash Tag Team Racing and Spyro).

The black bars on the sides when displaying 4:3 content will not be effected by shaders and might thus look lighter than the game image. If you find this distracting a (lighter) overlay will hide this issue.

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