diff --git a/tests/test_firmware_frames.py b/tests/test_firmware_frames.py
new file mode 100644
index 0000000..b9a1ad8
--- /dev/null
+++ b/tests/test_firmware_frames.py
@@ -0,0 +1,204 @@
+"""Host-side tests for firmware frame mode.
+
+Tests DRGB/DRGBW/DNRGB parsing and DNRGB multi-packet reassembly.
+Run with: python -m pytest tests/test_firmware_frames.py -v
+"""
+import sys
+import os
+import pytest
+
+sys.path.insert(0, os.path.join(os.path.dirname(__file__), '..', 'firmware'))
+
+from protocol import parse_drgb, parse_drgbw, parse_dnrgb, FrameAssembler
+from lightsync.protocol.drgb import encode_drgb, encode_drgbw, encode_dnrgb_packets
+
+
+class TestDRGBFrames:
+    def test_single_pixel(self):
+        packet = encode_drgb([(255, 0, 0)])
+        pixels = parse_drgb(packet)
+        assert pixels == [(255, 0, 0)]
+
+    def test_300_leds(self):
+        src = [(i % 256, (i * 7) % 256, (i * 13) % 256) for i in range(300)]
+        packet = encode_drgb(src)
+        pixels = parse_drgb(packet)
+        assert len(pixels) == 300
+        assert pixels[0] == src[0]
+        assert pixels[149] == src[149]
+        assert pixels[299] == src[299]
+
+    def test_all_black(self):
+        src = [(0, 0, 0)] * 100
+        packet = encode_drgb(src)
+        pixels = parse_drgb(packet)
+        assert all(p == (0, 0, 0) for p in pixels)
+
+    def test_all_white(self):
+        src = [(255, 255, 255)] * 50
+        packet = encode_drgb(src)
+        pixels = parse_drgb(packet)
+        assert all(p == (255, 255, 255) for p in pixels)
+
+
+class TestDRGBWFrames:
+    def test_single_pixel(self):
+        packet = encode_drgbw([(255, 0, 0, 128)])
+        pixels = parse_drgbw(packet)
+        assert pixels == [(255, 0, 0, 128)]
+
+    def test_300_leds_rgbw(self):
+        src = [(i % 256, (i * 3) % 256, (i * 5) % 256, (i * 7) % 256) for i in range(300)]
+        packet = encode_drgbw(src)
+        pixels = parse_drgbw(packet)
+        assert len(pixels) == 300
+        assert pixels[0] == src[0]
+        assert pixels[299] == src[299]
+
+    def test_w_channel_preserved(self):
+        """Verify the W channel survives encode/decode round-trip."""
+        src = [(100, 100, 100, 200)]
+        packet = encode_drgbw(src)
+        pixels = parse_drgbw(packet)
+        assert pixels[0][3] == 200
+
+
+class TestDNRGBFrames:
+    def test_single_packet_small(self):
+        src = [(255, 0, 0)] * 100
+        packets = encode_dnrgb_packets(src)
+        assert len(packets) == 1
+        start_idx, pixels = parse_dnrgb(packets[0])
+        assert start_idx == 0
+        assert len(pixels) == 100
+        assert pixels[0] == (255, 0, 0)
+
+    def test_multi_packet_600_leds(self):
+        """600 LEDs = 2 DNRGB packets (489 + 111)."""
+        src = [(i % 256, 0, 0) for i in range(600)]
+        packets = encode_dnrgb_packets(src)
+        assert len(packets) == 2
+
+        s0, px0 = parse_dnrgb(packets[0])
+        s1, px1 = parse_dnrgb(packets[1])
+
+        assert s0 == 0
+        assert s1 == 489
+        assert len(px0) == 489
+        assert len(px1) == 111
+
+        # Verify pixel values survive round-trip
+        assert px0[0] == src[0]
+        assert px0[488] == src[488]
+        assert px1[0] == src[489]
+        assert px1[110] == src[599]
+
+    def test_start_index_offset(self):
+        """Packets with non-zero start_index."""
+        src = [(0, 255, 0)] * 50
+        packets = encode_dnrgb_packets(src, start_index=100)
+        assert len(packets) == 1
+        start_idx, pixels = parse_dnrgb(packets[0])
+        assert start_idx == 100
+        assert len(pixels) == 50
+
+
+class TestFrameAssembler:
+    def test_single_chunk_completes(self):
+        asm = FrameAssembler(100)
+        pixels = [(i, 0, 0) for i in range(100)]
+        result = asm.feed(0, pixels, 1000)
+        assert result is not None
+        assert len(result) == 100
+        assert result[0] == (0, 0, 0)
+        assert result[99] == (99, 0, 0)
+
+    def test_two_chunks(self):
+        asm = FrameAssembler(200)
+        chunk1 = [(i, 0, 0) for i in range(100)]
+        chunk2 = [(100 + i, 0, 0) for i in range(100)]
+
+        result1 = asm.feed(0, chunk1, 1000)
+        assert result1 is None  # not complete yet
+
+        result2 = asm.feed(100, chunk2, 1010)
+        assert result2 is not None
+        assert len(result2) == 200
+        assert result2[0] == (0, 0, 0)
+        assert result2[100] == (100, 0, 0)
+        assert result2[199] == (199, 0, 0)
+
+    def test_timeout_clears_buffer(self):
+        asm = FrameAssembler(200)
+        chunk1 = [(i, 0, 0) for i in range(100)]
+
+        asm.feed(0, chunk1, 1000)
+        assert len(asm._buf) == 100
+
+        # Feed again after timeout (300ms > 200ms timeout)
+        chunk2 = [(50 + i, 0, 0) for i in range(50)]
+        asm.feed(0, chunk2, 1300)
+        # Buffer should have been cleared, only chunk2 remains
+        assert len(asm._buf) == 50
+
+    def test_reset(self):
+        asm = FrameAssembler(100)
+        asm.feed(0, [(0, 0, 0)] * 50, 1000)
+        asm.reset()
+        assert len(asm._buf) == 0
+
+    def test_full_round_trip_with_encoder(self):
+        """Multi-packet DNRGB: encode 600 LEDs -> feed both packets -> get complete frame."""
+        asm = FrameAssembler(600)
+        src = [(i % 256, (i * 3) % 256, (i * 7) % 256) for i in range(600)]
+        packets = encode_dnrgb_packets(src)
+        assert len(packets) == 2
+
+        s0, px0 = parse_dnrgb(packets[0])
+        result = asm.feed(s0, px0, 1000)
+        assert result is None
+
+        s1, px1 = parse_dnrgb(packets[1])
+        result = asm.feed(s1, px1, 1005)
+        assert result is not None
+        assert len(result) == 600
+        assert result[0] == src[0]
+        assert result[599] == src[599]
+
+
+class TestFrameModeIntegration:
+    """Test that SK6812 (RGBW) and WS2801 (RGB) frame paths work correctly."""
+
+    def test_drgb_for_ws2801(self):
+        """WS2801 is RGB — DRGB packets contain 3 bytes per pixel."""
+        src = [(255, 128, 64)] * 300
+        packet = encode_drgb(src)
+        pixels = parse_drgb(packet)
+        # All pixels should be RGB tuples
+        assert all(len(p) == 3 for p in pixels)
+        assert pixels[0] == (255, 128, 64)
+
+    def test_drgbw_for_sk6812(self):
+        """SK6812 is RGBW — DRGBW packets contain 4 bytes per pixel."""
+        src = [(255, 128, 64, 200)] * 300
+        packet = encode_drgbw(src)
+        pixels = parse_drgbw(packet)
+        # All pixels should be RGBW tuples
+        assert all(len(p) == 4 for p in pixels)
+        assert pixels[0] == (255, 128, 64, 200)
+
+    def test_drgb_pixel_count_matches(self):
+        """300 LED DRGB: 2 + 300*3 = 902 bytes, fits in one packet."""
+        src = [(0, 0, 0)] * 300
+        packet = encode_drgb(src)
+        assert len(packet) == 902
+        pixels = parse_drgb(packet)
+        assert len(pixels) == 300
+
+    def test_drgbw_pixel_count_matches(self):
+        """300 LED DRGBW: 2 + 300*4 = 1202 bytes, fits in one packet."""
+        src = [(0, 0, 0, 0)] * 300
+        packet = encode_drgbw(src)
+        assert len(packet) == 1202
+        pixels = parse_drgbw(packet)
+        assert len(pixels) == 300