diff --git a/src/hw_ostc3.c b/src/hw_ostc3.c
index 6f0354f..e240342 100644
--- a/src/hw_ostc3.c
+++ b/src/hw_ostc3.c
@@ -727,6 +727,11 @@ hw_ostc3_device_foreach (dc_device_t *abstract, dc_dive_callback_t callback, voi
 			if (firmware < 93)
 				length -= 3;
 		}
+		if (length < RB_LOGBOOK_SIZE_FULL) {
+			ERROR (abstract->context, "Invalid profile length (%u bytes).", length);
+			free (header);
+			return DC_STATUS_DATAFORMAT;
+		}
 
 		// Check the fingerprint data.
 		if (memcmp (header + offset + logbook->fingerprint, device->fingerprint, sizeof (device->fingerprint)) == 0)
@@ -789,6 +794,26 @@ hw_ostc3_device_foreach (dc_device_t *abstract, dc_dive_callback_t callback, voi
 			return rc;
 		}
 
+		// Detect invalid profile data.
+		unsigned int delta = device->hardware == OSTC4 ? 3 : 0;
+		if (length < RB_LOGBOOK_SIZE_FULL + 2 ||
+			profile[length - 2] != 0xFD || profile[length - 1] != 0xFD) {
+			// A valid profile should have at least a correct 2 byte
+			// end-of-profile marker.
+			WARNING (abstract->context, "Invalid profile end marker detected!");
+			length = RB_LOGBOOK_SIZE_FULL;
+		} 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 ||
+			array_uint24_le (profile + RB_LOGBOOK_SIZE_FULL) + delta != array_uint24_le (profile + 9)) {
+			// If there is more data available, then there should be a
+			// valid profile header containing a length matching the
+			// length in the dive header.
+			WARNING (abstract->context, "Invalid profile header detected.");
+			length = RB_LOGBOOK_SIZE_FULL;
+		}
+
 		if (callback && !callback (profile, length, profile + 12, sizeof (device->fingerprint), userdata))
 			break;
 	}
diff --git a/src/hw_ostc_parser.c b/src/hw_ostc_parser.c
index a96456c..04b9d6f 100644
--- a/src/hw_ostc_parser.c
+++ b/src/hw_ostc_parser.c
@@ -569,6 +569,13 @@ hw_ostc_parser_samples_foreach (dc_parser_t *abstract, dc_sample_callback_t call
 	unsigned int header = parser->header;
 	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)) {
+		parser->cached = PROFILE;
+		return DC_STATUS_SUCCESS;
+	}
+
 	// Check the header length.
 	if (version == 0x23 || version == 0x24) {
 		if (size < header + 5) {