diff --git a/Lua_scripts/MultiChan.txt b/Lua_scripts/MultiChan.txt
index b9dbd07..71550ca 100644
--- a/Lua_scripts/MultiChan.txt
+++ b/Lua_scripts/MultiChan.txt
@@ -198,7 +198,7 @@
 81,0,E010r5,E010r5,1,Flip,LED,CALIB,HLess,RTH,GLIDE
 82,0,LOLI,Std,0,CH5,CH6,CH7,CH8,1SwSePpPw,2SwSePw,3SwSe,4SwSe,5SwSeSb,6SwSe,7SwSePw,8SwSe
 83,0,E129,E129,1,TakLan,EmStop,TrimA,TrimE,TrimR
-83,1,E129,C186,1,TakLan,EmStop,TrimA,TrimE,TrimR
+83,1,E129,C186,1,TakLan,EmStop,TrimA,TrimE,TrimR,Loop
 84,0,JOYSWAY,Std,0
 85,0,E016H,Std,1,Stop,Flip,n-a,HLess,RTH
 87,0,IKEA
diff --git a/Multiprotocol/E129_cyrf6936.ino b/Multiprotocol/E129_cyrf6936.ino
index 160611d..8366c27 100644
--- a/Multiprotocol/E129_cyrf6936.ino
+++ b/Multiprotocol/E129_cyrf6936.ino
@@ -54,8 +54,9 @@ static void __attribute__((unused)) E129_build_data_packet()
 			packet[16] = bit_reverse(rx_tx_addr[1]);
 		}
 		//packet[ 3] = 0x00;							// E129 Mode: short press=0x20->0x00->0x20->..., long press=0x10->0x30->0x10->... => C186 throttle trim is doing the same:up=short press and down=long press
-		packet[ 4] = GET_FLAG(CH5_SW, 0x20)				// Take off/Land 0x20
-				   | GET_FLAG(CH6_SW, 0x04);			// Emergency stop 0x04
+		packet[ 3] = GET_FLAG(CH10_SW, 0x40);			// C159 loop flight 0x40, flag 0x04 is also set on this heli
+		packet[ 4] = GET_FLAG(CH5_SW,  0x20)			// Take off/Land 0x20
+				   | GET_FLAG(CH6_SW,  0x04);			// Emergency stop 0x04
 		//Channels and trims
 		uint16_t val = convert_channel_10b(AILERON,false);
 		uint8_t trim = convert_channel_8b(CH7) & 0xFC;
@@ -80,13 +81,11 @@ static void __attribute__((unused)) E129_build_data_packet()
 		packet[12] = val;								// channel (0x000...0x200...0x3FF)
 	}
 	//Check
-	if(sub_protocol == E129_E129)
-		packet[packet_length-2] = packet[0] + packet[1];
-	else
-		packet[packet_length-2] = 0x24 + packet[0] + (packet[1]&0x03);	// ??
-	for(uint8_t i=2;i<packet_length-2;i++)
+	for(uint8_t i=0;i<packet_length-2;i++)
 		packet[packet_length-2] += packet[i];
-		
+	if(sub_protocol == E129_C186)
+		packet[packet_length-2] -= 0x80;
+
 	RF2500_BuildPayload(packet);
 }
 
diff --git a/Multiprotocol/Multiprotocol.h b/Multiprotocol/Multiprotocol.h
index d729ff3..281150b 100644
--- a/Multiprotocol/Multiprotocol.h
+++ b/Multiprotocol/Multiprotocol.h
@@ -19,7 +19,7 @@
 #define VERSION_MAJOR		1
 #define VERSION_MINOR		3
 #define VERSION_REVISION	3
-#define VERSION_PATCH_LEVEL	33
+#define VERSION_PATCH_LEVEL	34
 
 #define MODE_SERIAL 0
 
diff --git a/Protocols_Details.md b/Protocols_Details.md
index 8102b55..a3eb6db 100644
--- a/Protocols_Details.md
+++ b/Protocols_Details.md
@@ -616,10 +616,16 @@ Calib is the same as the original radio with both sticks down and to the left in
 Models: Eachine E129/E130 and Twister Ninja 250
 
 ### Sub_protocol C186 - *1*
-Models: C186/E120, C127/E110, K127, C159
+Models: C186/E120, C127/E110, K127, C159, C189
 
 The FC of the heli seems to store the trims Trim A/E/R=CH7..9. If you use these trims, make sure to center them after powering off the heli or they will be added to the previous trims and over correct.
 
+CH10|
+---|
+Loop|
+
+Loop: circular flight on the C159 (others?)
+
 ## J6Pro - *22*
 
 CH1|CH2|CH3|CH4|CH5|CH6|CH7|CH8|CH9|CH10|CH11|CH12