diff --git a/ArduPlane/ReleaseNotes.txt b/ArduPlane/ReleaseNotes.txt
index 43b3da9b96..eb3c52135a 100644
--- a/ArduPlane/ReleaseNotes.txt
+++ b/ArduPlane/ReleaseNotes.txt
@@ -1,3 +1,7 @@
+Release 5.1.2 6th May 2024
+------------------------------
+- .github: added no crystal build for Carbonix AP_Periph boards
+ 
 Release 5.1.1 20th March 2024
 ------------------------------
 - AP_ICEngine: Added a new parameter CRANK_DIR for controlling the direction of engine cranking, providing flexibility in engine configurations.
diff --git a/libraries/AP_Common/AP_FWVersionDefine.h b/libraries/AP_Common/AP_FWVersionDefine.h
index 31d859cc35..1b00045c80 100644
--- a/libraries/AP_Common/AP_FWVersionDefine.h
+++ b/libraries/AP_Common/AP_FWVersionDefine.h
@@ -24,7 +24,7 @@
 #include <AP_Vehicle/AP_Vehicle_Type.h>
 
 #ifdef CARBOPILOT
-#define AP_CUSTOM_FIRMWARE_STRING "CxPilot 5.1.1"
+#define AP_CUSTOM_FIRMWARE_STRING "CxPilot 5.1.2"
 #endif
 
 /*