Hello.
I can't get Hyperion to work on a Rpi4 with a fresh install of latest Recalbox (7.2.2 at this time).
I've a (real) USB LightPack and at start the usual rainbow is well working but next... nothing.
If I launch hyperion manually with
hyperiond /recalbox/share/system/configs/hyperion/hyperion.config.json
I have some useful logs
Hyperion Ambilight Deamon (1117)
	Version   : (HEAD detached at 2d0d97e3b8) (digitalLumberjack-3b779a3ded/2d0d97e3b8-1623945268
	Build Time: Jun 17 2021 22:08:22
INFO: Selected configuration file: /recalbox/share/system/configs/hyperion/hyperion.config.json
HYPERION INFO: ColorTransform 'default' => [0; 29]
HYPERION INFO: ColorCorrection 'default' => [0; 29]
HYPERION INFO: ColorAdjustment 'default' => [0; 29]
LEDDEVICE INFO: configuration:
{
	"colorOrder" : "rgb",
	"name" : "MyHyperionConfig",
	"output" : "XXXXXX",
	"type" : "lightpack"
}
 
USB context initialized
Found a lightpack device. Retrieving more information...
Lightpack device found: bus=1 address=3 serial=XXXXXX
Lightpack device successfully opened
Lightpack device opened: bus=1 address=3 serial=XXXXXX version=6.5
INFO: Creating linear smoothing
HYPERION (CS) INFO: Created linear-smoothing(interval_ms=50;settlingTime_ms=200;updateDelay=0
EFFECTENGINE INFO: 27 effects loaded from directory /usr/share/hyperion/effects
EFFECTENGINE INFO: Initializing Python interpreter
INFO: Hyperion started and initialised
INFO: Boot sequence 'Rainbow swirl fast' EFFECTENGINE INFO: run effect Rainbow swirl fast on channel 0
BLACKBORDER INFO: threshold set to 0 (0)
BLACKBORDER INFO: mode:default
started
INFO: Json server created and started on port 19444
INFO: Proto server created and started on port 19445
QtHttpServer started on port 31168 "Qt Static HTTP File Server"
DISPMANXGRABBER INFO: Display opened with resolution: 4x1053479356
BLACKBORDER INFO: threshold set to 0 (0)
BLACKBORDER INFO: mode:default
INFO: Frame grabber created and started
DISPMANXGRABBER ERROR: Snapshot failed: -1
BORDER SWITCH REQUIRED!!
CURRENT BORDER TYPE: unknown=0 hor.size=0 vert.size=0
DISPMANXGRABBER ERROR: Snapshot failed: -1
DISPMANXGRABBER ERROR: Snapshot failed: -1
DISPMANXGRABBER ERROR: Snapshot failed: -1
DISPMANXGRABBER ERROR: Snapshot failed: -1
DISPMANXGRABBER ERROR: Snapshot failed: -1
DISPMANXGRABBER ERROR: Snapshot failed: -1
Where we can clearly see 2 errors
`BORDER SWITCH REQUIRED!!``
and
DISPMANXGRABBER ERROR: Snapshot failed: -1
Starting from there I've digged a little but didn't found anything relevant.
Here is my hyperion.config.json
{
	// DEVICE CONFIGURATION 
	"device" :
	{
		"name"       : "MyHyperionConfig",
		"type"       : "lightpack",
		"output"     : "XXXXXX",
		"colorOrder" : "rgb"
	},
	// COLOR CALIBRATION CONFIG
	"color" :
	{
		"channelAdjustment" :
		[
			{
				"id"   : "default",
				"leds" : "*",
				"pureRed" :
				{
					"redChannel"		: 255,
					"greenChannel"		: 0,
					"blueChannel"		: 0
				},
				"pureGreen" :
				{
					"redChannel"		: 0,
					"greenChannel"		: 255,
					"blueChannel"		: 0
				},
				"pureBlue" :
				{
					"redChannel"		: 0,
					"greenChannel"		: 0,
					"blueChannel"		: 255
				}
			}
		],
		"temperature" :
		[
			{
				"id"   : "default",
				"leds" : "*",
				"correctionValues" :
				{
					"red" 	: 255,
					"green"	: 255,
					"blue" 	: 255
				}
			}
		],
		"transform" :
		[
			{
				"id"   : "default",
				"leds" : "*",
				"hsl" :
				{
					"saturationGain"	: 1.0000,
					"luminanceGain"		: 1.0000,
					"luminanceMinimum"		: 0.0000
				},
				"red" :
				{
					"threshold" 	: 0.0000,
					"gamma"     	: 2.5000
				},
				"green" :
				{
					"threshold" 	: 0.0000,
					"gamma"     	: 2.5000
				},
				"blue" :
				{
					"threshold" 	: 0.0000,
					"gamma"     	: 2.5000
				}
			}
		],
	// SMOOTHING CONFIG
		"smoothing" :
		{
			"type"            : "linear",
			"time_ms"         : 200,
			"updateFrequency" : 20.0000,
			"updateDelay"     : 0
		}
	},
	// NO V4L2 GRABBER CONFIG
	// FRAME GRABBER CONFIG
	"framegrabber" : 
	{
		"width" : 64,
		"height" : 64,
		"frequency_Hz" : 10.0,
		"priority" : 890
	},
	// BLACKBORDER CONFIG
	"blackborderdetector" : 
	{
		"enable" : true,
		"threshold" : 0.0,
		"unknownFrameCnt" : 600,
		"borderFrameCnt" : 50,
		"maxInconsistentCnt" : 10,
		"blurRemoveCnt" : 1,
		"mode" : "default"
	},
	// BOOTEFFECT CONFIG
	"bootsequence" : 
	{
		"color" : [0,0,0],
		"effect" : "Rainbow swirl fast",
		"duration_ms" : 3000,
		"priority" : 700
	},
	// JSON SERVER CONFIG
	"jsonServer" : 
	{
		"port" : 19444
	},
	// PROTO SERVER CONFIG
	"protoServer" : 
	{
		"port" : 19445
	},
	// EFFECT PATH
	"effects" : 
	{
		"paths" : 
		[
			"/storage/hyperion/effects",
			"/usr/share/hyperion/effects"
		]
	},
	// NO KODI CHECK CONFIG
	// NO BOBLIGHT SERVER CONFIG
	// NO JSON/PROTO FORWARD CONFIG
	// LED CONFIGURATION
	"leds" : 
	[
		{
			"index" : 0,
			"hscan" : { "minimum" : 0.0000, "maximum" : 0.1667 },
			"vscan" : { "minimum" : 0.0000, "maximum" : 0.0800 }
		},
		{
			"index" : 1,
			"hscan" : { "minimum" : 0.1667, "maximum" : 0.3333 },
			"vscan" : { "minimum" : 0.0000, "maximum" : 0.0800 }
		},
		{
			"index" : 2,
			"hscan" : { "minimum" : 0.3333, "maximum" : 0.5000 },
			"vscan" : { "minimum" : 0.0000, "maximum" : 0.0800 }
		},
		{
			"index" : 3,
			"hscan" : { "minimum" : 0.5000, "maximum" : 0.6667 },
			"vscan" : { "minimum" : 0.0000, "maximum" : 0.0800 }
		},
		{
			"index" : 4,
			"hscan" : { "minimum" : 0.6667, "maximum" : 0.8333 },
			"vscan" : { "minimum" : 0.0000, "maximum" : 0.0800 }
		},
		{
			"index" : 5,
			"hscan" : { "minimum" : 0.8333, "maximum" : 1.0000 },
			"vscan" : { "minimum" : 0.0000, "maximum" : 0.0800 }
		},
		{
			"index" : 6,
			"hscan" : { "minimum" : 0.9500, "maximum" : 1.0000 },
			"vscan" : { "minimum" : 0.0000, "maximum" : 0.0833 }
		},
		{
			"index" : 7,
			"hscan" : { "minimum" : 0.9500, "maximum" : 1.0000 },
			"vscan" : { "minimum" : 0.0833, "maximum" : 0.1667 }
		},
		{
			"index" : 8,
			"hscan" : { "minimum" : 0.9500, "maximum" : 1.0000 },
			"vscan" : { "minimum" : 0.1667, "maximum" : 0.2500 }
		},
		{
			"index" : 9,
			"hscan" : { "minimum" : 0.9500, "maximum" : 1.0000 },
			"vscan" : { "minimum" : 0.2500, "maximum" : 0.3333 }
		},
		{
			"index" : 10,
			"hscan" : { "minimum" : 0.9500, "maximum" : 1.0000 },
			"vscan" : { "minimum" : 0.3333, "maximum" : 0.4167 }
		},
		{
			"index" : 11,
			"hscan" : { "minimum" : 0.9500, "maximum" : 1.0000 },
			"vscan" : { "minimum" : 0.4167, "maximum" : 0.5000 }
		},
		{
			"index" : 12,
			"hscan" : { "minimum" : 0.9500, "maximum" : 1.0000 },
			"vscan" : { "minimum" : 0.5000, "maximum" : 0.5833 }
		},
		{
			"index" : 13,
			"hscan" : { "minimum" : 0.9500, "maximum" : 1.0000 },
			"vscan" : { "minimum" : 0.5833, "maximum" : 0.6667 }
		},
		{
			"index" : 14,
			"hscan" : { "minimum" : 0.9500, "maximum" : 1.0000 },
			"vscan" : { "minimum" : 0.6667, "maximum" : 0.7500 }
		},
		{
			"index" : 15,
			"hscan" : { "minimum" : 0.9500, "maximum" : 1.0000 },
			"vscan" : { "minimum" : 0.7500, "maximum" : 0.8333 }
		},
		{
			"index" : 16,
			"hscan" : { "minimum" : 0.9500, "maximum" : 1.0000 },
			"vscan" : { "minimum" : 0.8333, "maximum" : 0.9167 }
		},
		{
			"index" : 17,
			"hscan" : { "minimum" : 0.9500, "maximum" : 1.0000 },
			"vscan" : { "minimum" : 0.9167, "maximum" : 1.0000 }
		},
		{
			"index" : 18,
			"hscan" : { "minimum" : 0.0000, "maximum" : 0.0500 },
			"vscan" : { "minimum" : 0.9167, "maximum" : 1.0000 }
		},
		{
			"index" : 19,
			"hscan" : { "minimum" : 0.0000, "maximum" : 0.0500 },
			"vscan" : { "minimum" : 0.8333, "maximum" : 0.9167 }
		},
		{
			"index" : 20,
			"hscan" : { "minimum" : 0.0000, "maximum" : 0.0500 },
			"vscan" : { "minimum" : 0.7500, "maximum" : 0.8333 }
		},
		{
			"index" : 21,
			"hscan" : { "minimum" : 0.0000, "maximum" : 0.0500 },
			"vscan" : { "minimum" : 0.6667, "maximum" : 0.7500 }
		},
		{
			"index" : 22,
			"hscan" : { "minimum" : 0.0000, "maximum" : 0.0500 },
			"vscan" : { "minimum" : 0.5833, "maximum" : 0.6667 }
		},
		{
			"index" : 23,
			"hscan" : { "minimum" : 0.0000, "maximum" : 0.0500 },
			"vscan" : { "minimum" : 0.5000, "maximum" : 0.5833 }
		},
		{
			"index" : 24,
			"hscan" : { "minimum" : 0.0000, "maximum" : 0.0500 },
			"vscan" : { "minimum" : 0.4167, "maximum" : 0.5000 }
		},
		{
			"index" : 25,
			"hscan" : { "minimum" : 0.0000, "maximum" : 0.0500 },
			"vscan" : { "minimum" : 0.3333, "maximum" : 0.4167 }
		},
		{
			"index" : 26,
			"hscan" : { "minimum" : 0.0000, "maximum" : 0.0500 },
			"vscan" : { "minimum" : 0.2500, "maximum" : 0.3333 }
		},
		{
			"index" : 27,
			"hscan" : { "minimum" : 0.0000, "maximum" : 0.0500 },
			"vscan" : { "minimum" : 0.1667, "maximum" : 0.2500 }
		},
		{
			"index" : 28,
			"hscan" : { "minimum" : 0.0000, "maximum" : 0.0500 },
			"vscan" : { "minimum" : 0.0833, "maximum" : 0.1667 }
		},
		{
			"index" : 29,
			"hscan" : { "minimum" : 0.0000, "maximum" : 0.0500 },
			"vscan" : { "minimum" : 0.0000, "maximum" : 0.0833 }
		}
	],
	"endOfJson" : "endOfJson"
}
So I wondering if it's possible to use another grabber?
or if someone as a working config on a Rpi4 + R7.2?
Thanks for your help.