diff --git a/README.md b/README.md
index 2f6b9ad..73e01a8 100644
--- a/README.md
+++ b/README.md
@@ -157,6 +157,7 @@ Before we start, I want to encourage you with some hobbyist builds.
 ### RGB Light
   * All RGB lights are daisy-chained in just one WS2812B chain following this order:
     * [8x Button Nodes] -> [3x Cabinet Nodes] -> [1x Banner Node] -> [1x AIME Node]
+    * 3 Cabinet Nodes are: main body, display bezel, side panel.
   * You can set chained RGB LED numbers for each node (Button, Cabinet or Banner) using `rgb` command. `0` means ignore the nodes. Note that AIME node supports up to 16 LEDs, and you can't change it.
   * If two or more RGB LEDs are connected parallelly (sharing the same input), they're considered as one node.
 
diff --git a/README_CN.md b/README_CN.md
index a76e837..92dd61f 100644
--- a/README_CN.md
+++ b/README_CN.md
@@ -160,6 +160,7 @@
 ### RGB 灯光
   * 所有 WS2812 LED 都是串接在一条 RGB 线路上的，顺序如下：
     * [8x 按钮节点] --> [3x 机框节点] --> [1x 顶灯节点] --> [1x AIME 节点]
+    * 3 个机框节点分别是：机身、画面外环、机框侧面。
   * 你可以使用 `rgb` 命令为每个节点（按钮、机框或顶灯）设置串联的 RGB LED 数量。设置 `0` 表示忽略该类节点。请注意，AIME 节点支持最多 16 个 LED，且无法更改。
   * 如果多个 RGB LED 并联（共享相同输入），则视为一个节点。
 
diff --git a/firmware/src/io.c b/firmware/src/io.c
index fc22387..a6b0557 100644
--- a/firmware/src/io.c
+++ b/firmware/src/io.c
@@ -22,7 +22,7 @@ typedef union {
     uint8_t raw[28];
     struct {
         uint8_t body;
-        uint8_t ext;
+        uint8_t bezel;
         uint8_t side;
     };
     struct {
@@ -251,9 +251,10 @@ static void led_cmd(cdc_t *cdc)
             }
             break;
         case 0x39:
-            DEBUG(led, "LED Fet\n");
+            DEBUG(led, "LED Cabinet %02x %02x %02x\n",
+                  cdc->led.body, cdc->led.bezel, cdc->led.side);
             rgb_set_cab(0, gray32(cdc->led.body, false));
-            rgb_set_cab(1, gray32(cdc->led.ext, false));
+            rgb_set_cab(1, gray32(cdc->led.bezel, false));
             rgb_set_cab(2, gray32(cdc->led.side, false));
             break;