diff --git a/contrib/udev/libdivecomputer.rules b/contrib/udev/libdivecomputer.rules
index 14d0ce6..e4e6fdc 100644
--- a/contrib/udev/libdivecomputer.rules
+++ b/contrib/udev/libdivecomputer.rules
@@ -17,7 +17,7 @@ SUBSYSTEM=="usb", ATTR{idVendor}=="2e6c", ATTR{idProduct}=="3201", GROUP="plugde
 SUBSYSTEM=="usb", ATTR{idVendor}=="2e6c", ATTR{idProduct}=="3211", GROUP="plugdev"
 
 # Scubapro G2 HUD
-SUBSYSTEM=="usb", ATTR{idVendor}=="2e6c", ATTR{idProduct}=="0x4201", GROUP="plugdev"
+SUBSYSTEM=="usb", ATTR{idVendor}=="2e6c", ATTR{idProduct}=="4201", GROUP="plugdev"
 
 # Scubapro Aladin Square
 SUBSYSTEM=="usb", ATTR{idVendor}=="c251", ATTR{idProduct}=="2006", GROUP="plugdev"
diff --git a/examples/dctool_fwupdate.c b/examples/dctool_fwupdate.c
index e5daf35..596ccb1 100644
--- a/examples/dctool_fwupdate.c
+++ b/examples/dctool_fwupdate.c
@@ -35,6 +35,7 @@
 #include <libdivecomputer/device.h>
 #include <libdivecomputer/hw_ostc.h>
 #include <libdivecomputer/hw_ostc3.h>
+#include <libdivecomputer/divesystem_idive.h>
 
 #include "dctool.h"
 #include "common.h"
@@ -93,6 +94,9 @@ fwupdate (dc_context_t *context, dc_descriptor_t *descriptor, dc_transport_t tra
 	case DC_FAMILY_HW_OSTC3:
 		rc = hw_ostc3_device_fwupdate (device, hexfile);
 		break;
+	case DC_FAMILY_DIVESYSTEM_IDIVE:
+		rc = divesystem_idive_device_fwupdate (device, hexfile);
+		break;
 	default:
 		rc = DC_STATUS_UNSUPPORTED;
 		break;
diff --git a/include/libdivecomputer/Makefile.am b/include/libdivecomputer/Makefile.am
index 8e12f2d..e972153 100644
--- a/include/libdivecomputer/Makefile.am
+++ b/include/libdivecomputer/Makefile.am
@@ -28,4 +28,5 @@ libdivecomputer_HEADERS = 	\
 	hw_ostc.h \
 	hw_frog.h \
 	hw_ostc3.h \
-	atomics_cobalt.h
+	atomics_cobalt.h \
+	divesystem_idive.h
diff --git a/include/libdivecomputer/divesystem_idive.h b/include/libdivecomputer/divesystem_idive.h
new file mode 100644
index 0000000..07065d1
--- /dev/null
+++ b/include/libdivecomputer/divesystem_idive.h
@@ -0,0 +1,38 @@
+/*
+ * libdivecomputer
+ *
+ * Copyright (C) 2019 Jef Driesen
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
+ * MA 02110-1301 USA
+ */
+
+#ifndef DC_DIVESYSTEM_IDIVE_H
+#define DC_DIVESYSTEM_IDIVE_H
+
+#include "common.h"
+#include "device.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif /* __cplusplus */
+
+dc_status_t
+divesystem_idive_device_fwupdate (dc_device_t *abstract, const char *filename);
+
+#ifdef __cplusplus
+}
+#endif /* __cplusplus */
+#endif /* DC_DIVESYSTEM_IDIVE_H */
diff --git a/src/descriptor.c b/src/descriptor.c
index f7731b7..4db368d 100644
--- a/src/descriptor.c
+++ b/src/descriptor.c
@@ -584,10 +584,11 @@ static int dc_filter_mares (dc_transport_t transport, const void *userdata)
 {
 	static const char * const bluetooth[] = {
 		"Mares bluelink pro",
+		"Mares Genius",
 	};
 
 	if (transport == DC_TRANSPORT_BLE) {
-		return DC_FILTER_INTERNAL (userdata, bluetooth, 0, dc_match_name);
+		return DC_FILTER_INTERNAL (userdata, bluetooth, 0, dc_match_prefix);
 	}
 
 	return 1;
diff --git a/src/divesystem_idive.c b/src/divesystem_idive.c
index 1c71de9..0659d06 100644
--- a/src/divesystem_idive.c
+++ b/src/divesystem_idive.c
@@ -21,10 +21,12 @@
 
 #include <string.h> // memcmp, memcpy
 #include <stdlib.h> // malloc, free
+#include <stdio.h>
 
 #include "divesystem_idive.h"
 #include "context-private.h"
 #include "device-private.h"
+#include "platform.h"
 #include "checksum.h"
 #include "array.h"
 
@@ -39,6 +41,7 @@
 #define MAXPACKET 0xFF
 #define START     0x55
 #define ACK       0x06
+#define WAIT      0x13
 #define NAK       0x15
 
 #define CMD_IDIVE_ID      0x10
@@ -51,6 +54,12 @@
 #define CMD_IX3M_HEADER   0x79
 #define CMD_IX3M_SAMPLE   0x7A
 #define CMD_IX3M_TIMESYNC 0x13
+#define CMD_IX3M_BOOTLOADER 0x0A
+
+#define BOOTLOADER_PROBE    0x78
+#define BOOTLOADER_UPLOAD_A 0x40
+#define BOOTLOADER_UPLOAD_B 0x23
+#define BOOTLOADER_ACK      0x46
 
 #define ERR_INVALID_CMD    0x10
 #define ERR_INVALID_LENGTH 0x20
@@ -80,6 +89,11 @@ typedef struct divesystem_idive_commands_t {
 	unsigned int nsamples;
 } divesystem_idive_commands_t;
 
+typedef struct divesystem_idive_signature_t {
+	const char *name;
+	unsigned int delay;
+} divesystem_idive_signature_t;
+
 typedef struct divesystem_idive_device_t {
 	dc_device_t base;
 	dc_iostream_t *iostream;
@@ -127,6 +141,14 @@ static const divesystem_idive_commands_t ix3m_apos4 = {
 	3,
 };
 
+static const divesystem_idive_signature_t signatures[] = {
+	{"dsh01", 50}, // IX3M GPS
+	{"dsh30", 50}, // IX3M Pro
+	{"dsh20",  5}, // iDive Sport
+	{"dsh23",  5}, // iDive Color
+	{"acx",    5}, // WPT
+};
+
 dc_status_t
 divesystem_idive_device_open (dc_device_t **out, dc_context_t *context, dc_iostream_t *iostream, unsigned int model)
 {
@@ -652,3 +674,262 @@ divesystem_idive_device_timesync (dc_device_t *abstract, const dc_datetime_t *da
 
 	return DC_STATUS_SUCCESS;
 }
+
+static dc_status_t
+divesystem_idive_firmware_readfile (dc_buffer_t *buffer, dc_context_t *context, const char *filename)
+{
+	dc_status_t status = DC_STATUS_SUCCESS;
+	dc_buffer_t *tmp = NULL;
+	FILE *fp = NULL;
+
+	if (!dc_buffer_clear (buffer)) {
+		ERROR (context, "Invalid arguments.");
+		return DC_STATUS_INVALIDARGS;
+	}
+
+	// Allocate a temporary buffer.
+	tmp = dc_buffer_new (0x20000);
+	if (tmp == NULL) {
+		ERROR (context, "Failed to allocate memory.");
+		status = DC_STATUS_NOMEMORY;
+		goto error_exit;
+	}
+
+	// Open the file.
+	fp = fopen (filename, "rb");
+	if (fp == NULL) {
+		ERROR (context, "Failed to open the file.");
+		status = DC_STATUS_IO;
+		goto error_free;
+	}
+
+	// Read the entire file into the buffer.
+	size_t n = 0;
+	unsigned char block[4096] = {0};
+	while ((n = fread (block, 1, sizeof (block), fp)) > 0) {
+		if (!dc_buffer_append (tmp, block, n)) {
+			ERROR (context, "Insufficient buffer space available.");
+			status = DC_STATUS_NOMEMORY;
+			goto error_close;
+		}
+	}
+
+	// Resize the output buffer.
+	size_t nbytes = dc_buffer_get_size (tmp);
+	if (!dc_buffer_resize (buffer, nbytes / 2)) {
+		ERROR (context, "Insufficient buffer space available.");
+		status = DC_STATUS_NOMEMORY;
+		goto error_close;
+	}
+
+	// Convert to binary data.
+	int rc = array_convert_hex2bin (
+		dc_buffer_get_data (tmp), dc_buffer_get_size (tmp),
+		dc_buffer_get_data (buffer), dc_buffer_get_size (buffer));
+	if (rc != 0) {
+		ERROR (context, "Unexpected data format.");
+		status = DC_STATUS_DATAFORMAT;
+		goto error_close;
+	}
+
+error_close:
+	fclose (fp);
+error_free:
+	dc_buffer_free (tmp);
+error_exit:
+	return status;
+}
+
+static dc_status_t
+divesystem_idive_firmware_send (divesystem_idive_device_t *device, const divesystem_idive_signature_t *signature, const unsigned char data[], size_t size)
+{
+	dc_status_t status = DC_STATUS_SUCCESS;
+	dc_device_t *abstract = (dc_device_t *) device;
+
+	unsigned int nretries = 0;
+	while (1) {
+		// Send the frame.
+		status = dc_iostream_write (device->iostream, data, size, NULL);
+		if (status != DC_STATUS_SUCCESS) {
+			ERROR (abstract->context, "Failed to send the frame.");
+			return status;
+		}
+
+		// Read the response until an ACK or NAK byte is received.
+		unsigned int state = 0;
+		while (state == 0) {
+			// Receive the response.
+			unsigned char response = 0;
+			status = dc_iostream_read (device->iostream, &response, 1, NULL);
+			if (status != DC_STATUS_SUCCESS) {
+				ERROR (abstract->context, "Failed to receive the response.");
+				return status;
+			}
+
+			// Process the response.
+			switch (response) {
+			case ACK:
+			case NAK:
+				state = response;
+				break;
+			case WAIT:
+				dc_iostream_sleep (device->iostream, signature->delay);
+				break;
+			case 'A':
+			case 'B':
+			case 'C':
+			case 'D':
+			case 'E':
+			case 'F':
+			case 'G':
+			case 'H':
+			case 'K':
+			case 'X':
+				break;
+			default:
+				WARNING (abstract->context, "Unexpected response byte received (%02x)", response);
+				break;
+			}
+		}
+
+		// Exit if ACK received.
+		if (state == ACK)
+			break;
+
+		// Abort if the maximum number of retries is reached.
+		if (nretries++ >= MAXRETRIES) {
+			ERROR (abstract->context, "Maximum number of retries reached.");
+			return DC_STATUS_PROTOCOL;
+		}
+	}
+
+	return DC_STATUS_SUCCESS;
+}
+
+dc_status_t
+divesystem_idive_device_fwupdate (dc_device_t *abstract, const char *filename)
+{
+	dc_status_t status = DC_STATUS_SUCCESS;
+	divesystem_idive_device_t *device = (divesystem_idive_device_t *) abstract;
+	unsigned int errcode = 0;
+
+	// Allocate memory for the firmware data.
+	dc_buffer_t *buffer = dc_buffer_new (0);
+	if (buffer == NULL) {
+		ERROR (abstract->context, "Failed to allocate memory for the firmware data.");
+		status = DC_STATUS_NOMEMORY;
+		goto error_exit;
+	}
+
+	// Read the firmware file.
+	status = divesystem_idive_firmware_readfile (buffer, abstract->context, filename);
+	if (status != DC_STATUS_SUCCESS) {
+		ERROR (abstract->context, "Failed to read the firmware file.");
+		goto error_free;
+	}
+
+	// Cache the data and size.
+	const unsigned char *data = dc_buffer_get_data (buffer);
+	size_t size = dc_buffer_get_size (buffer);
+
+	// Enable progress notifications.
+	dc_event_progress_t progress = EVENT_PROGRESS_INITIALIZER;
+	progress.maximum = size;
+	device_event_emit (abstract, DC_EVENT_PROGRESS, &progress);
+
+	// Activate the bootloader.
+	const unsigned char bootloader[] = {CMD_IX3M_BOOTLOADER, 0xC9, 0x4B};
+	status = divesystem_idive_transfer (device, bootloader, sizeof (bootloader), NULL, 0, &errcode);
+	if (status != DC_STATUS_SUCCESS) {
+		ERROR (abstract->context, "Failed to activate the bootloader.");
+		goto error_free;
+	}
+
+	// Give the device some time to enter the bootloader.
+	dc_iostream_sleep (device->iostream, 2000);
+
+	// Wait for the bootloader.
+	const divesystem_idive_signature_t *signature = NULL;
+	while (signature == NULL) {
+		// Discard garbage data.
+		dc_iostream_purge (device->iostream, DC_DIRECTION_INPUT);
+
+		// Probe for the bootloader.
+		const unsigned char probe[] = {BOOTLOADER_PROBE};
+		status = dc_iostream_write (device->iostream, probe, sizeof (probe), NULL);
+		if (status != DC_STATUS_SUCCESS) {
+			ERROR (abstract->context, "Failed to activate the bootloader.");
+			goto error_free;
+		}
+
+		// Read the signature string.
+		size_t n = 0;
+		unsigned char name[5] = {0};
+		status = dc_iostream_read (device->iostream, name, sizeof (name), &n);
+		if (status != DC_STATUS_SUCCESS && status != DC_STATUS_TIMEOUT) {
+			ERROR (abstract->context, "Failed to read the signature string.");
+			goto error_free;
+		}
+
+		// Verify the signature string.
+		for (size_t i = 0; i < C_ARRAY_SIZE (signatures); ++i) {
+			if (n == strlen (signatures[i].name) && memcmp (name, signatures[i].name, n) == 0) {
+				signature = signatures + i;
+				break;
+			}
+		}
+	}
+
+	// Send the start upload command.
+	const unsigned char upload[] = {BOOTLOADER_UPLOAD_A, BOOTLOADER_UPLOAD_B};
+	status = dc_iostream_write (device->iostream, upload, sizeof(upload), NULL);
+	if (status != DC_STATUS_SUCCESS) {
+		ERROR (abstract->context, "Failed to send the start upload command.");
+		goto error_free;
+	}
+
+	// Receive the ack.
+	unsigned char ack[1] = {0};
+	status = dc_iostream_read (device->iostream, ack, sizeof(ack), NULL);
+	if (status != DC_STATUS_SUCCESS) {
+		ERROR (abstract->context, "Failed to receive the ack byte.");
+		goto error_free;
+	}
+
+	// Verify the ack.
+	if (ack[0] != BOOTLOADER_ACK) {
+		ERROR (abstract->context, "Invalid ack byte (%02x).", ack[0]);
+		status = DC_STATUS_PROTOCOL;
+		goto error_free;
+	}
+
+	// Upload the firmware.
+	unsigned int offset = 0;
+	while (offset + 2 <= size) {
+		// Get the number of bytes in the current frame.
+		unsigned int len = array_uint16_be (data + offset) + 2;
+		if (offset + len > size) {
+			ERROR (abstract->context, "Invalid frame size (%u %u " DC_PRINTF_SIZE ")", offset, len, size);
+			status = DC_STATUS_DATAFORMAT;
+			goto error_free;
+		}
+
+		// Send the frame.
+		status = divesystem_idive_firmware_send (device, signature, data + offset, len);
+		if (status != DC_STATUS_SUCCESS) {
+			ERROR (abstract->context, "Failed to send the frame.");
+			goto error_free;
+		}
+
+		// Update and emit a progress event.
+		progress.current += len;
+		device_event_emit (abstract, DC_EVENT_PROGRESS, &progress);
+
+		offset += len;
+	}
+
+error_free:
+	dc_buffer_free (buffer);
+error_exit:
+	return status;
+}
diff --git a/src/divesystem_idive.h b/src/divesystem_idive.h
index 8c79866..1da80a0 100644
--- a/src/divesystem_idive.h
+++ b/src/divesystem_idive.h
@@ -26,6 +26,7 @@
 #include <libdivecomputer/iostream.h>
 #include <libdivecomputer/device.h>
 #include <libdivecomputer/parser.h>
+#include <libdivecomputer/divesystem_idive.h>
 
 #ifdef __cplusplus
 extern "C" {
diff --git a/src/hw_ostc.h b/src/hw_ostc.h
index 8232e5d..5635e6d 100644
--- a/src/hw_ostc.h
+++ b/src/hw_ostc.h
@@ -36,7 +36,7 @@ dc_status_t
 hw_ostc_device_open (dc_device_t **device, dc_context_t *context, dc_iostream_t *iostream);
 
 dc_status_t
-hw_ostc_parser_create (dc_parser_t **parser, dc_context_t *context, unsigned int serial, unsigned int hwos);
+hw_ostc_parser_create (dc_parser_t **parser, dc_context_t *context, unsigned int serial);
 
 #ifdef __cplusplus
 }
diff --git a/src/hw_ostc3.c b/src/hw_ostc3.c
index 187a9e4..0521e2e 100644
--- a/src/hw_ostc3.c
+++ b/src/hw_ostc3.c
@@ -713,7 +713,6 @@ hw_ostc3_device_foreach (dc_device_t *abstract, dc_dive_callback_t callback, voi
 	// The device maintains an internal counter which is incremented for every
 	// dive, and the current value at the time of the dive is stored in the
 	// dive header. Thus the most recent dive will have the highest value.
-	unsigned int count = 0;
 	unsigned int latest = 0;
 	unsigned int maximum = 0;
 	for (unsigned int i = 0; i < RB_LOGBOOK_COUNT; ++i) {
@@ -729,24 +728,21 @@ hw_ostc3_device_foreach (dc_device_t *abstract, dc_dive_callback_t callback, voi
 			maximum = current;
 			latest = i;
 		}
-
-		count++;
 	}
 
 	// Calculate the total and maximum size.
 	unsigned int ndives = 0;
 	unsigned int size = 0;
 	unsigned int maxsize = 0;
-	for (unsigned int i = 0; i < count; ++i) {
+	unsigned char dive[RB_LOGBOOK_COUNT] = {0};
+	for (unsigned int i = 0; i < RB_LOGBOOK_COUNT; ++i) {
 		unsigned int idx = (latest + RB_LOGBOOK_COUNT - i) % RB_LOGBOOK_COUNT;
 		unsigned int offset = idx * logbook->size;
 
-		// Uninitialized header entries should no longer be present at this
-		// stage, unless the dives are interleaved with empty entries. But
-		// that's something we don't support at all.
+		// Ignore uninitialized header entries.
 		if (array_isequal (header + offset, logbook->size, 0xFF)) {
 			WARNING (abstract->context, "Unexpected empty header found.");
-			break;
+			continue;
 		}
 
 		// Calculate the profile length.
@@ -770,6 +766,7 @@ hw_ostc3_device_foreach (dc_device_t *abstract, dc_dive_callback_t callback, voi
 		if (length > maxsize)
 			maxsize = length;
 		size += length;
+		dive[ndives] = idx;
 		ndives++;
 	}
 
@@ -793,7 +790,7 @@ hw_ostc3_device_foreach (dc_device_t *abstract, dc_dive_callback_t callback, voi
 
 	// Download the dives.
 	for (unsigned int i = 0; i < ndives; ++i) {
-		unsigned int idx = (latest + RB_LOGBOOK_COUNT - i) % RB_LOGBOOK_COUNT;
+		unsigned int idx = dive[i];
 		unsigned int offset = idx * logbook->size;
 
 		// Calculate the profile length.
diff --git a/src/hw_ostc_parser.c b/src/hw_ostc_parser.c
index 1f82b07..7a7817e 100644
--- a/src/hw_ostc_parser.c
+++ b/src/hw_ostc_parser.c
@@ -49,6 +49,14 @@
 #define HEADER  1
 #define PROFILE 2
 
+#define TEMPERATURE 0
+#define DECO        1
+#define GF          2
+#define PPO2        3
+#define DECOPLAN    4
+#define CNS         5
+#define TANK        6
+
 #define OSTC_ZHL16_OC    0
 #define OSTC_GAUGE       1
 #define OSTC_ZHL16_CC    2
@@ -75,6 +83,16 @@
 
 #define UNSUPPORTED 0xFFFFFFFF
 
+#define OSTC3FW(major,minor) ( \
+		(((major) & 0xFF) << 8) | \
+		((minor) & 0xFF))
+
+#define OSTC4FW(major,minor,micro,beta) ( \
+		(((major) & 0x1F) << 11) | \
+		(((minor) & 0x1F) >> 6) | \
+		(((micro) & 0x1F) << 1) | \
+		((beta) & 0x01))
+
 typedef struct hw_ostc_sample_info_t {
 	unsigned int type;
 	unsigned int divisor;
@@ -370,9 +388,9 @@ hw_ostc_parser_create_internal (dc_parser_t **out, dc_context_t *context, unsign
 
 
 dc_status_t
-hw_ostc_parser_create (dc_parser_t **out, dc_context_t *context, unsigned int serial, unsigned int hwos)
+hw_ostc_parser_create (dc_parser_t **out, dc_context_t *context, unsigned int serial)
 {
-	return hw_ostc_parser_create_internal (out, context, serial, hwos, 0);
+	return hw_ostc_parser_create_internal (out, context, serial, 0, 0);
 }
 
 dc_status_t
@@ -757,21 +775,21 @@ hw_ostc_parser_samples_foreach (dc_parser_t *abstract, dc_sample_callback_t call
 
 		if (info[i].divisor) {
 			switch (info[i].type) {
-			case 0: // Temperature
-			case 1: // Deco / NDL
-			case 6: // Tank pressure
+			case TEMPERATURE:
+			case DECO:
+			case TANK:
 				if (info[i].size != 2) {
 					ERROR(abstract->context, "Unexpected sample size.");
 					return DC_STATUS_DATAFORMAT;
 				}
 				break;
-			case 3: // ppO2
+			case PPO2:
 				if (info[i].size != 3 && info[i].size != 9) {
 					ERROR(abstract->context, "Unexpected sample size.");
 					return DC_STATUS_DATAFORMAT;
 				}
 				break;
-			case 5: // CNS
+			case CNS:
 				if (info[i].size != 1 && info[i].size != 2) {
 					ERROR(abstract->context, "Unexpected sample size.");
 					return DC_STATUS_DATAFORMAT;
@@ -978,6 +996,17 @@ hw_ostc_parser_samples_foreach (dc_parser_t *abstract, dc_sample_callback_t call
 		for (unsigned int i = 0; i < nconfig; ++i) {
 			if (info[i].divisor && (nsamples % info[i].divisor) == 0) {
 				if (length < info[i].size) {
+					// Due to a bug in the hwOS Tech firmware v3.03 to v3.07, and
+					// the hwOS Sport firmware v10.57 to v10.63, the ppO2 divisor
+					// is sometimes not correctly reset to zero when no ppO2
+					// samples are being recorded.
+					if (info[i].type == PPO2 && parser->hwos && parser->model != OSTC4 &&
+						((firmware >= OSTC3FW(3,3) && firmware <= OSTC3FW(3,7)) ||
+						(firmware >= OSTC3FW(10,57) && firmware <= OSTC3FW(10,63)))) {
+						WARNING (abstract->context, "Reset invalid ppO2 divisor to zero.");
+						info[i].divisor = 0;
+						continue;
+					}
 					ERROR (abstract->context, "Buffer overflow detected!");
 					return DC_STATUS_DATAFORMAT;
 				}
@@ -986,15 +1015,15 @@ hw_ostc_parser_samples_foreach (dc_parser_t *abstract, dc_sample_callback_t call
 				unsigned int count = 0;
 				unsigned int value = 0;
 				switch (info[i].type) {
-				case 0: // Temperature (0.1 °C).
+				case TEMPERATURE:
 					value = array_uint16_le (data + offset);
 					sample.temperature = value / 10.0;
 					if (callback) callback (DC_SAMPLE_TEMPERATURE, sample, userdata);
 					break;
-				case 1: // Deco / NDL
+				case DECO:
 					// Due to a firmware bug, the deco/ndl info is incorrect for
 					// all OSTC4 dives with a firmware older than version 1.0.8.
-					if (parser->model == OSTC4 && firmware < 0x0810)
+					if (parser->model == OSTC4 && firmware < OSTC4FW(1,0,8,0))
 						break;
 					if (data[offset]) {
 						sample.deco.type = DC_DECO_DECOSTOP;
@@ -1006,7 +1035,7 @@ hw_ostc_parser_samples_foreach (dc_parser_t *abstract, dc_sample_callback_t call
 					sample.deco.time = data[offset + 1] * 60;
 					if (callback) callback (DC_SAMPLE_DECO, sample, userdata);
 					break;
-				case 3: // ppO2 (0.01 bar).
+				case PPO2:
 					for (unsigned int j = 0; j < 3; ++j) {
 						if (info[i].size == 3) {
 							ppo2[j] = data[offset + j];
@@ -1023,18 +1052,24 @@ hw_ostc_parser_samples_foreach (dc_parser_t *abstract, dc_sample_callback_t call
 						}
 					}
 					break;
-				case 5: // CNS
+				case CNS:
 					if (info[i].size == 2)
 						sample.cns = array_uint16_le (data + offset) / 100.0;
 					else
 						sample.cns = data[offset] / 100.0;
 					if (callback) callback (DC_SAMPLE_CNS, sample, userdata);
 					break;
-				case 6: // Tank pressure
+				case TANK:
 					value = array_uint16_le (data + offset);
 					if (value != 0) {
 						sample.pressure.tank = tank;
-						sample.pressure.value = value / 10.0;
+						sample.pressure.value = value;
+						// The hwOS Sport firmware used a resolution of
+						// 0.1 bar between versions 10.40 and 10.50.
+						if (parser->hwos && parser->model != OSTC4 &&
+							(firmware >= OSTC3FW(10,40) && firmware <= OSTC3FW(10,50))) {
+							sample.pressure.value /= 10.0;
+						}
 						if (callback) callback (DC_SAMPLE_PRESSURE, sample, userdata);
 					}
 					break;
diff --git a/src/libdivecomputer.symbols b/src/libdivecomputer.symbols
index eeb7240..bb553a0 100644
--- a/src/libdivecomputer.symbols
+++ b/src/libdivecomputer.symbols
@@ -144,3 +144,4 @@ hw_ostc3_device_config_reset
 hw_ostc3_device_fwupdate
 atomics_cobalt_device_version
 atomics_cobalt_device_set_simulation
+divesystem_idive_device_fwupdate
diff --git a/src/oceanic_atom2.c b/src/oceanic_atom2.c
index c3fe75a..42152f0 100644
--- a/src/oceanic_atom2.c
+++ b/src/oceanic_atom2.c
@@ -124,7 +124,8 @@ static const oceanic_common_version_t oceanic_atom2b_version[] = {
 	{"AQUAI300 \0\0 512K"},
 	{"HOLLDG03 \0\0 512K"},
 	{"AQUAI100 \0\0 512K"},
-	{"AQUA300C \0\0 \0\0\0\0"},
+	{"AQUA300C \0\0 512K"},
+	{"OCEGEO40 \0\0 512K"},
 };
 
 static const oceanic_common_version_t oceanic_atom2c_version[] = {
@@ -139,7 +140,6 @@ static const oceanic_common_version_t oceanic_default_version[] = {
 	{"ELITET31 \0\0 512K"},
 	{"DATAMASK \0\0 512K"},
 	{"COMPMASK \0\0 512K"},
-	{"OCEGEO40 \0\0 512K"},
 };
 
 static const oceanic_common_version_t sherwood_wisdom_version[] = {
diff --git a/src/parser.c b/src/parser.c
index 5e347bd..8fd16ee 100644
--- a/src/parser.c
+++ b/src/parser.c
@@ -134,7 +134,7 @@ dc_parser_new_internal (dc_parser_t **out, dc_context_t *context, dc_family_t fa
 		rc = mares_iconhd_parser_create (&parser, context, model);
 		break;
 	case DC_FAMILY_HW_OSTC:
-		rc = hw_ostc_parser_create (&parser, context, serial, 0);
+		rc = hw_ostc_parser_create (&parser, context, serial);
 		break;
 	case DC_FAMILY_HW_FROG:
 	case DC_FAMILY_HW_OSTC3: