diff --git a/src/hw_ostc3.c b/src/hw_ostc3.c
index cfb25d7..7b87587 100644
--- a/src/hw_ostc3.c
+++ b/src/hw_ostc3.c
@@ -869,7 +869,7 @@ hw_ostc3_device_foreach (dc_device_t *abstract, dc_dive_callback_t callback, voi
 		} else if (length == RB_LOGBOOK_SIZE_FULL + 2) {
 			// A profile containing only the 2 byte end-of-profile
 			// marker is considered a valid empty profile.
-		} else if (length < RB_LOGBOOK_SIZE_FULL + 5 + 2 ||
+		} else if (length < RB_LOGBOOK_SIZE_FULL + 5 ||
 			array_uint24_le (profile + RB_LOGBOOK_SIZE_FULL) + delta != array_uint24_le (profile + HDR_FULL_LENGTH)) {
 			// If there is more data available, then there should be a
 			// valid profile header containing a length matching the
diff --git a/src/hw_ostc_parser.c b/src/hw_ostc_parser.c
index 90994f8..d745ef8 100644
--- a/src/hw_ostc_parser.c
+++ b/src/hw_ostc_parser.c
@@ -20,6 +20,7 @@
  */
 
 #include <stdlib.h>
+#include <string.h>
 
 #include "libdivecomputer/units.h"
 
@@ -679,8 +680,10 @@ hw_ostc_parser_samples_foreach (dc_parser_t *abstract, dc_sample_callback_t call
 	const hw_ostc_layout_t *layout = parser->layout;
 
 	// Exit if no profile data available.
-	if (size == header || (size == header + 2 &&
-		data[header] == 0xFD && data[header + 1] == 0xFD)) {
+	const unsigned char empty[] = {0x08, 0x00, 0x00, 0xFD, 0xFD};
+	if (size == header ||
+		(size == header + 2 && memcmp(data + header, empty + 3, 2) == 0) ||
+		(size == header + 5 && memcmp(data + header, empty, 5) == 0)) {
 		parser->cached = PROFILE;
 		return DC_STATUS_SUCCESS;
 	}