Add led colors and remove an unnecessary photo

doc/devices/FG-4GT-2SX_V2.0.md

@@ -4,10 +4,6 @@ Following is documentation for unmanaged switch marked as `FG-4GT-2SX_V2.0`.
 
 Original software is running UART on 9600 baud rate.
 
-The signal quality of UART is bad. Therefore, electrical isolation is needed for the TTL wires in some cases. A simple way to isolate them is to pinch them by fingers.
-
-<img src="photos/FG-4GT-2SX_V2.0/electrical_isolation.png" width="300" />
-
 ## Brands
 
 * Ruiying RY-4GT-2SX

machine.c

@@ -1089,6 +1089,10 @@ __code const struct machine machine = {
 	.reset_pin = GPIO_NA,
 	.high_leds = { .mux = LED_27 | LED_28_SYS | LED_29, .enable = LED_28_SYS | LED_29 },
 	.port_led_set = { 0, 0, 0, 1, 0, 0, 0, 0, 1},
+	/* Ports 1-5 RJ45 use set 0, port 9 SFP uses set 1 
+	 * Ports 1-5: Green: 2.5GBit, Amber: 10/100/1000MBit
+	 * SFP-port: Green: 100MBit-10GBit
+	 */
 	.led_sets = { 
 			{
 				LEDS_2G5 | LEDS_LINK | LEDS_ACT,
@@ -1126,7 +1130,6 @@ __code const struct machine machine = {
 	};
 
 void machine_custom_init(void) {
-	// Match the OEM LED pad enable mask, including port 4 and SDS0 LEDs.
 	REG_SET(RTL837X_REG_LED_GLB_IO_EN, 0x7624155b);
 }