diff --git a/settings/controller_mapping_manager.gd b/settings/controller_mapping_manager.gd
index dad32b4..b1040bc 100644
--- a/settings/controller_mapping_manager.gd
+++ b/settings/controller_mapping_manager.gd
@@ -12,19 +12,19 @@ const PROFILE_BACKUP_PATH: String = "user://controller_mappings.json.backup"
 const MAX_PROFILE_BYTES: int = 1024 * 1024
 const CAPTURE_AXIS_THRESHOLD: float = 0.55
 const CAPTURE_AXIS_RELEASE_THRESHOLD: float = 0.30
-const MUOS_MAPPING_REVISION: String = "muos-v1"
+const MUOS_MAPPING_REVISION: String = "muos-v2"
 const MUOS_CONTROLLER_NAMES: Array[String] = [
 	"muOS-Keys",
 	"Deeplay-keys",
 ]
 const MUOS_MAPPING_BINDINGS: String = (
-	"a:b3,b:b4,x:b6,y:b5,"
-	+ "leftshoulder:b7,rightshoulder:b8,"
-	+ "lefttrigger:b13,righttrigger:b14,"
-	+ "guide:b11,start:b10,back:b9,"
+	"a:b2,b:b0,x:b1,y:b3,"
+	+ "leftshoulder:b6,rightshoulder:b7,"
+	+ "lefttrigger:b8,righttrigger:b9,"
+	+ "guide:b12,start:b11,back:b10,"
 	+ "dpup:h0.1,dpleft:h0.8,dpright:h0.2,dpdown:h0.4,"
-	+ "leftx:a0,lefty:a1,leftstick:b12,"
-	+ "rightx:a2,righty:a3,rightstick:b15,platform:Linux,"
+	+ "leftx:a0,lefty:a1,leftstick:b4,"
+	+ "rightx:a2,righty:a3,rightstick:b5,platform:Linux,"
 )
 const ROLE_A: StringName = &"a"
 const ROLE_B: StringName = &"b"
@@ -605,7 +605,10 @@ func _install_known_controller_mappings() -> void:
 
 func _install_known_controller_mapping(device_id: int) -> bool:
 	var controller_name: String = Input.get_joy_name(device_id).strip_edges()
-	if controller_name not in MUOS_CONTROLLER_NAMES:
+	if not should_install_muos_compatibility_mapping(
+		controller_name,
+		Input.is_joy_known(device_id),
+	):
 		return false
 	var guid: String = Input.get_joy_guid(device_id).strip_edges()
 	if guid.is_empty():
@@ -635,6 +638,15 @@ static func is_muos_controller_name(controller_name: String) -> bool:
 	return controller_name.strip_edges() in MUOS_CONTROLLER_NAMES
 
 
+static func should_install_muos_compatibility_mapping(
+	controller_name: String,
+	is_known: bool,
+) -> bool:
+	# Current SDL databases should remain authoritative. This fallback exists
+	# only for legacy muOS virtual controllers that SDL cannot identify.
+	return is_muos_controller_name(controller_name) and not is_known
+
+
 func _set_active_controller(device_id: int) -> void:
 	var previous_profile_key: String = _active_profile_key
 	_active_device_id = maxi(device_id, 0)
diff --git a/tests/controller_mapping_validation.gd b/tests/controller_mapping_validation.gd
index e155a71..614f15b 100644
--- a/tests/controller_mapping_validation.gd
+++ b/tests/controller_mapping_validation.gd
@@ -40,10 +40,16 @@ func _validate_manager(manager: ControllerMappingManagerType) -> String:
 		)
 	)
 	for expected_binding: String in [
-		"a:b3",
-		"b:b4",
-		"x:b6",
-		"y:b5",
+		"a:b2",
+		"b:b0",
+		"x:b1",
+		"y:b3",
+		"leftshoulder:b6",
+		"rightshoulder:b7",
+		"lefttrigger:b8",
+		"righttrigger:b9",
+		"back:b10",
+		"start:b11",
 		"leftx:a0",
 		"righty:a3",
 	]:
@@ -61,6 +67,21 @@ func _validate_manager(manager: ControllerMappingManagerType) -> String:
 		"ordinary controller"
 	):
 		return "muOS mapping would affect unrelated controllers"
+	if not ControllerMappingManagerType.should_install_muos_compatibility_mapping(
+		"muOS-Keys",
+		false,
+	):
+		return "unknown legacy muOS controller did not receive fallback mapping"
+	if ControllerMappingManagerType.should_install_muos_compatibility_mapping(
+		"muOS-Keys",
+		true,
+	):
+		return "recognized muOS controller would override its SDL mapping"
+	if ControllerMappingManagerType.should_install_muos_compatibility_mapping(
+		"ordinary controller",
+		false,
+	):
+		return "muOS fallback would affect an unrelated unknown controller"
 	var defaults: Dictionary = manager.get_active_bindings()
 	if defaults.size() != ControllerMappingManagerType.ROLE_ORDER.size():
 		return "default mapping covers %d of %d controller roles: %s" % [