diff --git a/hardware/common/dmm/fs9721.c b/hardware/common/dmm/fs9721.c
index 41b08f71..6a55c716 100644
--- a/hardware/common/dmm/fs9721.c
+++ b/hardware/common/dmm/fs9721.c
@@ -326,11 +326,6 @@ static void handle_flags(struct sr_datafeed_analog *analog, float *floatval,
 		sr_spew("User-defined LCD symbol 3 is active.");
 }
 
-SR_PRIV gboolean sr_fs9721_is_packet_start(uint8_t b)
-{
-	return (((b >> 4) & 0x0f) == 0x01);
-}
-
 SR_PRIV gboolean sr_fs9721_packet_valid(const uint8_t *buf)
 {
 	struct fs9721_info info;
diff --git a/libsigrok-internal.h b/libsigrok-internal.h
index b16b29a0..6e1cac2d 100644
--- a/libsigrok-internal.h
+++ b/libsigrok-internal.h
@@ -210,7 +210,6 @@ struct fs9922_info {
 	int bargraph_sign, bargraph_value;
 };
 
-SR_PRIV gboolean sr_fs9922_is_packet_start(uint8_t b);
 SR_PRIV gboolean sr_fs9922_packet_valid(const uint8_t *buf);
 SR_PRIV int sr_fs9922_parse(const uint8_t *buf, float *floatval,
 			    struct sr_datafeed_analog *analog, void *info);
@@ -226,7 +225,6 @@ struct fs9721_info {
 	gboolean is_c2c1_11, is_c2c1_10, is_c2c1_01, is_c2c1_00, is_sign;
 };
 
-SR_PRIV gboolean sr_fs9721_is_packet_start(uint8_t b);
 SR_PRIV gboolean sr_fs9721_packet_valid(const uint8_t *buf);
 SR_PRIV int sr_fs9721_parse(const uint8_t *buf, float *floatval,
 			    struct sr_datafeed_analog *analog, void *info);