diff --git a/README.md b/README.md
index 8867480..d6fe3b5 100644
--- a/README.md
+++ b/README.md
@@ -19,6 +19,11 @@ The device settings have a "Key test" option (column or row sweep) to check the
 - The keyboard shows each packet as it arrives, so `len` must be a multiple of 3. With the stock
   plugin's 56, LEDs 18, 74 and 93 (W, O, Menu) are split across packets and flash random colours.
 - The keyboard falls back to its own effect when frames stop, so colours must be streamed.
+  The plugin only sends packets whose colours changed, plus a full frame every 500 ms.
+- The keyboard echoes every colour packet's header back as an input report. The plugin waits
+  for that echo (up to 10 ms) before the next packet, as OpenRGB's EVision driver does.
+- OpenRGB supports this keyboard (`EVision Keyboard 320F:502A`) but only through the saved
+  custom-colour command (`0x11` between begin `0x01` / end `0x02`), not a live mode.
 
 ## LED map
 
@@ -32,3 +37,5 @@ Right Ctrl 101, arrows 109 / 117 / 125.
 - `tools/evision_led.ps1` sends test frames straight to the keyboard, e.g.
   `evision_led.ps1 -Leds "0=ff0000,21=00ff00" -Seconds 60` lights LED 0 red and 21 green for a minute.
   Used to map the LEDs; quit SignalRGB first so the two don't fight over the device.
+- `tools/evision_listen.ps1` passively reads the RGB endpoint's input reports (the packet echoes)
+  for a few seconds, grouped by header. Safe to run while SignalRGB is streaming.
diff --git a/Womier_K87_EVision.js b/Womier_K87_EVision.js
index 1133784..2262379 100644
--- a/Womier_K87_EVision.js
+++ b/Womier_K87_EVision.js
@@ -85,6 +85,7 @@ export function Render() {
 }
 
 export function Shutdown(SystemSuspending) {
+	lastFullRefresh = 0; // always send the whole frame
 	sendColors(SystemSuspending ? "#000000" : shutdownColor);
 }
 
@@ -117,16 +118,37 @@ function sendColors(overrideColor) {
 	writeRGBPackage(RGBData);
 }
 
+// Last packet sent per offset, so unchanged packets can be skipped
+let sentPackets = {};
+let lastFullRefresh = 0;
+
 function writeRGBPackage(RGBData) {
 	// Must be a multiple of 3: the keyboard shows each packet as it arrives, so an LED split
 	// across two packets briefly flashes a mix of its old and new colour
 	const bytesToSend = lowFPS ? 48 : 54;
 
+	// Resend everything twice a second so the keyboard never falls back to its own effect
+	const now = Date.now();
+	const fullRefresh = now - lastFullRefresh >= 500;
+
+	if (fullRefresh) {
+		lastFullRefresh = now;
+		sentPackets = {};
+	}
+
 	for (let offset = 0; offset < RGBData.length; offset += bytesToSend) {
 		const data = RGBData.slice(offset, offset + bytesToSend);
 
 		while (data.length < bytesToSend) { data.push(0); }
 
+		const key = `${bytesToSend}:${data.join(",")}`;
+
+		if (sentPackets[offset] === key) {
+			continue;
+		}
+
+		sentPackets[offset] = key;
+
 		const packet = [0x04, 0x00, 0x00, 0x12, bytesToSend, offset & 0xFF, (offset >> 8) & 0xFF, 0x00].concat(data);
 
 		// Checksum: 16-bit sum of bytes 3..end (same result as the EVision plugin's formula)
@@ -139,6 +161,10 @@ function writeRGBPackage(RGBData) {
 
 		device.write(packet, 64);
 
+		// The keyboard echoes each packet back; wait for it (as OpenRGB does) so the next
+		// packet doesn't arrive while it's still processing this one
+		device.read([0x04], 64, 10);
+
 		// device.pause() rounds up to the Windows timer tick (up to ~15 ms), so only pause when asked
 		if (lowFPS) { device.pause(3); }
 	}
diff --git a/tools/evision_listen.ps1 b/tools/evision_listen.ps1
new file mode 100644
index 0000000..ee43c99
--- /dev/null
+++ b/tools/evision_listen.ps1
@@ -0,0 +1,35 @@
+# Passively reads input reports from the EVision RGB endpoint for a few seconds
+param([double]$Seconds = 2, [string]$Match = 'VID_320F&PID_502A&MI_01&COL04')
+Add-Type @"
+using System;
+using System.IO;
+using System.Runtime.InteropServices;
+using Microsoft.Win32.SafeHandles;
+public static class EVL {
+  [DllImport("kernel32.dll", SetLastError=true, CharSet=CharSet.Unicode)]
+  public static extern SafeFileHandle CreateFile(string n, uint a, uint s, IntPtr sa, uint c, uint f, IntPtr t);
+  public static string Listen(string path, int ms) {
+    var h = CreateFile(path, 0x80000000, 3, IntPtr.Zero, 3, 0x40000000, IntPtr.Zero);
+    if (h.IsInvalid) return "open failed " + Marshal.GetLastWin32Error();
+    var sb = new System.Text.StringBuilder();
+    var counts = new System.Collections.Generic.Dictionary<string,int>();
+    using (var fs = new FileStream(h, FileAccess.Read, 64, true)) {
+      var end = DateTime.Now.AddMilliseconds(ms); int n = 0;
+      while (DateTime.Now < end) {
+        var buf = new byte[64];
+        var t = fs.ReadAsync(buf, 0, 64);
+        if (!t.Wait(end - DateTime.Now > TimeSpan.Zero ? end - DateTime.Now : TimeSpan.Zero)) break;
+        n++;
+        var key = BitConverter.ToString(buf, 0, 8);
+        counts[key] = counts.ContainsKey(key) ? counts[key] + 1 : 1;
+      }
+      sb.AppendLine("reports: " + n);
+      foreach (var kv in counts) sb.AppendLine(kv.Value + "x  " + kv.Key);
+    }
+    return sb.ToString();
+  }
+}
+"@
+$dev = Get-PnpDevice -PresentOnly -Class HIDClass | Where-Object { $_.InstanceId -match [regex]::Escape($Match) } | Select-Object -First 1
+$path = '\\?\' + ($dev.InstanceId -replace '\\','#') + '#{4d1e55b2-f16f-11cf-88cb-001111000030}'
+[EVL]::Listen($path, [int]($Seconds * 1000))