diff --git a/src/main/common/streambuf.c b/src/main/common/streambuf.c
index 910fe99c78..c055ad61ae 100644
--- a/src/main/common/streambuf.c
+++ b/src/main/common/streambuf.c
@@ -62,7 +62,7 @@ void sbufWriteData(sbuf_t *dst, const void *data, int len)
 
 void sbufWriteString(sbuf_t *dst, const char *string)
 {
-    sbufWriteData(dst, string, strlen(string) + 1); // include zero terminator
+    sbufWriteData(dst, string, strlen(string));
 }
 
 uint8_t sbufReadU8(sbuf_t *src)
diff --git a/src/main/telemetry/crsf.c b/src/main/telemetry/crsf.c
index 69f9eb73bb..34e8878ad7 100644
--- a/src/main/telemetry/crsf.c
+++ b/src/main/telemetry/crsf.c
@@ -204,7 +204,7 @@ void crsfFrameAttitude(sbuf_t *dst)
 /*
 0x21 Flight mode text based
 Payload:
-char[]      Flight mode ( Null­terminated string )
+char[]      Flight mode ( Null­terminated string )
 */
 void crsfFrameFlightMode(sbuf_t *dst)
 {
@@ -226,6 +226,7 @@ void crsfFrameFlightMode(sbuf_t *dst)
         flightMode = "HOR";
     }
     sbufWriteString(dst, flightMode);
+    sbufWriteU8(dst, '\0');     // zero-terminate string
     // write in the frame length
     *lengthPtr = sbufPtr(dst) - lengthPtr;
 }