diff --git a/frigate/detectors/detection_runners.py b/frigate/detectors/detection_runners.py
index da7df9d36..0c2b46f56 100644
--- a/frigate/detectors/detection_runners.py
+++ b/frigate/detectors/detection_runners.py
@@ -527,6 +527,15 @@ class RKNNModelRunner(BaseModelRunner):
                             # Transpose from NCHW to NHWC
                             pixel_data = np.transpose(pixel_data, (0, 2, 3, 1))
                         rknn_inputs.append(pixel_data)
+                    elif name == "data":
+                        # ArcFace: undo Python normalisation to uint8 [0,255]
+                        # RKNN runtime applies mean=127.5/std=127.5 internally before first layer
+                        face_data = inputs[name]
+                        if len(face_data.shape) == 4 and face_data.shape[1] == 3:
+                            # Transpose from NCHW to NHWC
+                            face_data = np.transpose(face_data, (0, 2, 3, 1))
+                        face_data = ((face_data + 1.0) * 127.5).clip(0, 255).astype(np.uint8)
+                        rknn_inputs.append(face_data)
                     else:
                         rknn_inputs.append(inputs[name])