diff --git a/samples/bluetooth/central/src/main.c b/samples/bluetooth/central/src/main.c
index ec5a703ce4..05d835add0 100644
--- a/samples/bluetooth/central/src/main.c
+++ b/samples/bluetooth/central/src/main.c
@@ -81,7 +81,7 @@ static void disconnected(struct bt_conn *conn, u8_t reason)
 
 	bt_addr_le_to_str(bt_conn_get_dst(conn), addr, sizeof(addr));
 
-	printk("Disconnected: %s (reason %u)\n", addr, reason);
+	printk("Disconnected: %s (reason 0x%02x)\n", addr, reason);
 
 	bt_conn_unref(default_conn);
 	default_conn = NULL;
diff --git a/samples/bluetooth/central_hr/src/main.c b/samples/bluetooth/central_hr/src/main.c
index db503167b1..2ac270f2ff 100644
--- a/samples/bluetooth/central_hr/src/main.c
+++ b/samples/bluetooth/central_hr/src/main.c
@@ -187,7 +187,7 @@ static void disconnected(struct bt_conn *conn, u8_t reason)
 
 	bt_addr_le_to_str(bt_conn_get_dst(conn), addr, sizeof(addr));
 
-	printk("Disconnected: %s (reason %u)\n", addr, reason);
+	printk("Disconnected: %s (reason 0x%02x)\n", addr, reason);
 
 	if (default_conn != conn) {
 		return;
diff --git a/samples/bluetooth/eddystone/src/main.c b/samples/bluetooth/eddystone/src/main.c
index 47b31bc4b2..78cfcdbc01 100644
--- a/samples/bluetooth/eddystone/src/main.c
+++ b/samples/bluetooth/eddystone/src/main.c
@@ -649,7 +649,7 @@ static void idle_timeout(struct k_work *work)
 static void connected(struct bt_conn *conn, u8_t err)
 {
 	if (err) {
-		printk("Connection failed (err %u)\n", err);
+		printk("Connection failed (err 0x%02x)\n", err);
 	} else {
 		printk("Connected\n");
 		k_delayed_work_cancel(&idle_work);
@@ -660,7 +660,7 @@ static void disconnected(struct bt_conn *conn, u8_t reason)
 {
 	struct eds_slot *slot = &eds_slots[eds_active_slot];
 
-	printk("Disconnected (reason %u)\n", reason);
+	printk("Disconnected (reason 0x%02x)\n", reason);
 
 	if (!slot->connectable) {
 		k_delayed_work_submit(&idle_work, 0);
diff --git a/samples/bluetooth/peripheral/src/main.c b/samples/bluetooth/peripheral/src/main.c
index 1b23d1998b..a1450edcaa 100644
--- a/samples/bluetooth/peripheral/src/main.c
+++ b/samples/bluetooth/peripheral/src/main.c
@@ -229,7 +229,7 @@ static const struct bt_data ad[] = {
 static void connected(struct bt_conn *conn, u8_t err)
 {
 	if (err) {
-		printk("Connection failed (err %u)\n", err);
+		printk("Connection failed (err 0x%02x)\n", err);
 	} else {
 		printk("Connected\n");
 	}
@@ -237,7 +237,7 @@ static void connected(struct bt_conn *conn, u8_t err)
 
 static void disconnected(struct bt_conn *conn, u8_t reason)
 {
-	printk("Disconnected (reason %u)\n", reason);
+	printk("Disconnected (reason 0x%02x)\n", reason);
 }
 
 static struct bt_conn_cb conn_callbacks = {
diff --git a/samples/bluetooth/peripheral_csc/src/main.c b/samples/bluetooth/peripheral_csc/src/main.c
index 1e47f064a4..719f8e03dc 100644
--- a/samples/bluetooth/peripheral_csc/src/main.c
+++ b/samples/bluetooth/peripheral_csc/src/main.c
@@ -344,7 +344,7 @@ static void csc_simulation(void)
 static void connected(struct bt_conn *conn, u8_t err)
 {
 	if (err) {
-		printk("Connection failed (err %u)\n", err);
+		printk("Connection failed (err 0x%02x)\n", err);
 	} else {
 		printk("Connected\n");
 	}
@@ -352,7 +352,7 @@ static void connected(struct bt_conn *conn, u8_t err)
 
 static void disconnected(struct bt_conn *conn, u8_t reason)
 {
-	printk("Disconnected (reason %u)\n", reason);
+	printk("Disconnected (reason 0x%02x)\n", reason);
 }
 
 static struct bt_conn_cb conn_callbacks = {
diff --git a/samples/bluetooth/peripheral_dis/src/main.c b/samples/bluetooth/peripheral_dis/src/main.c
index b84e985d92..aa51251323 100644
--- a/samples/bluetooth/peripheral_dis/src/main.c
+++ b/samples/bluetooth/peripheral_dis/src/main.c
@@ -29,7 +29,7 @@ static const struct bt_data ad[] = {
 static void connected(struct bt_conn *conn, u8_t err)
 {
 	if (err) {
-		printk("Connection failed (err %u)\n", err);
+		printk("Connection failed (err 0x%02x)\n", err);
 	} else {
 		printk("Connected\n");
 	}
@@ -37,7 +37,7 @@ static void connected(struct bt_conn *conn, u8_t err)
 
 static void disconnected(struct bt_conn *conn, u8_t reason)
 {
-	printk("Disconnected (reason %u)\n", reason);
+	printk("Disconnected (reason 0x%02x)\n", reason);
 }
 
 static struct bt_conn_cb conn_callbacks = {
diff --git a/samples/bluetooth/peripheral_esp/src/main.c b/samples/bluetooth/peripheral_esp/src/main.c
index f821007608..f23b01c15b 100644
--- a/samples/bluetooth/peripheral_esp/src/main.c
+++ b/samples/bluetooth/peripheral_esp/src/main.c
@@ -361,7 +361,7 @@ static const struct bt_data ad[] = {
 static void connected(struct bt_conn *conn, u8_t err)
 {
 	if (err) {
-		printk("Connection failed (err %u)\n", err);
+		printk("Connection failed (err 0x%02x)\n", err);
 	} else {
 		printk("Connected\n");
 	}
@@ -369,7 +369,7 @@ static void connected(struct bt_conn *conn, u8_t err)
 
 static void disconnected(struct bt_conn *conn, u8_t reason)
 {
-	printk("Disconnected (reason %u)\n", reason);
+	printk("Disconnected (reason 0x%02x)\n", reason);
 }
 
 static struct bt_conn_cb conn_callbacks = {
diff --git a/samples/bluetooth/peripheral_hids/src/main.c b/samples/bluetooth/peripheral_hids/src/main.c
index 1a9499ec88..2addbef829 100644
--- a/samples/bluetooth/peripheral_hids/src/main.c
+++ b/samples/bluetooth/peripheral_hids/src/main.c
@@ -55,7 +55,7 @@ static void disconnected(struct bt_conn *conn, u8_t reason)
 
 	bt_addr_le_to_str(bt_conn_get_dst(conn), addr, sizeof(addr));
 
-	printk("Disconnected from %s (reason %u)\n", addr, reason);
+	printk("Disconnected from %s (reason 0x%02x)\n", addr, reason);
 }
 
 static void security_changed(struct bt_conn *conn, bt_security_t level)
diff --git a/samples/bluetooth/peripheral_hr/src/main.c b/samples/bluetooth/peripheral_hr/src/main.c
index 30fd6c7365..143bb6c640 100644
--- a/samples/bluetooth/peripheral_hr/src/main.c
+++ b/samples/bluetooth/peripheral_hr/src/main.c
@@ -32,7 +32,7 @@ static const struct bt_data ad[] = {
 static void connected(struct bt_conn *conn, u8_t err)
 {
 	if (err) {
-		printk("Connection failed (err %u)\n", err);
+		printk("Connection failed (err 0x%02x)\n", err);
 	} else {
 		default_conn = bt_conn_ref(conn);
 		printk("Connected\n");
@@ -41,7 +41,7 @@ static void connected(struct bt_conn *conn, u8_t err)
 
 static void disconnected(struct bt_conn *conn, u8_t reason)
 {
-	printk("Disconnected (reason %u)\n", reason);
+	printk("Disconnected (reason 0x%02x)\n", reason);
 
 	if (default_conn) {
 		bt_conn_unref(default_conn);
diff --git a/samples/bluetooth/peripheral_ht/src/main.c b/samples/bluetooth/peripheral_ht/src/main.c
index 3310bc5054..2107641823 100644
--- a/samples/bluetooth/peripheral_ht/src/main.c
+++ b/samples/bluetooth/peripheral_ht/src/main.c
@@ -36,7 +36,7 @@ static const struct bt_data ad[] = {
 static void connected(struct bt_conn *conn, u8_t err)
 {
 	if (err) {
-		printk("Connection failed (err %u)\n", err);
+		printk("Connection failed (err 0x%02x)\n", err);
 	} else {
 		default_conn = bt_conn_ref(conn);
 		printk("Connected\n");
@@ -45,7 +45,7 @@ static void connected(struct bt_conn *conn, u8_t err)
 
 static void disconnected(struct bt_conn *conn, u8_t reason)
 {
-	printk("Disconnected (reason %u)\n", reason);
+	printk("Disconnected (reason 0x%02x)\n", reason);
 
 	if (default_conn) {
 		bt_conn_unref(default_conn);
diff --git a/samples/bluetooth/peripheral_sc_only/src/main.c b/samples/bluetooth/peripheral_sc_only/src/main.c
index 2c13b23856..1e7dbe8e22 100644
--- a/samples/bluetooth/peripheral_sc_only/src/main.c
+++ b/samples/bluetooth/peripheral_sc_only/src/main.c
@@ -48,7 +48,7 @@ static void disconnected(struct bt_conn *conn, u8_t reason)
 
 	bt_addr_le_to_str(bt_conn_get_dst(conn), addr, sizeof(addr));
 
-	printk("Disconnected from %s (reason %u)\n", addr, reason);
+	printk("Disconnected from %s (reason 0x%02x)\n", addr, reason);
 }
 
 static void identity_resolved(struct bt_conn *conn, const bt_addr_le_t *rpa,
diff --git a/samples/boards/bbc_microbit/pong/src/ble.c b/samples/boards/bbc_microbit/pong/src/ble.c
index 2f9afcca88..15e9d1cb86 100644
--- a/samples/boards/bbc_microbit/pong/src/ble.c
+++ b/samples/boards/bbc_microbit/pong/src/ble.c
@@ -230,7 +230,7 @@ static void connected(struct bt_conn *conn, u8_t err)
 	struct bt_conn_info info;
 
 	if (err) {
-		printk("Connection failed (err %u)\n", err);
+		printk("Connection failed (err 0x%02x)\n", err);
 		return;
 	}
 
@@ -255,7 +255,7 @@ static void connected(struct bt_conn *conn, u8_t err)
 
 static void disconnected(struct bt_conn *conn, u8_t reason)
 {
-	printk("Disconnected (reason %u)\n", reason);
+	printk("Disconnected (reason 0x%02x)\n", reason);
 
 	if (default_conn) {
 		bt_conn_unref(default_conn);
diff --git a/samples/subsys/mgmt/mcumgr/smp_svr/src/main.c b/samples/subsys/mgmt/mcumgr/smp_svr/src/main.c
index 960582136d..6f737b018a 100644
--- a/samples/subsys/mgmt/mcumgr/smp_svr/src/main.c
+++ b/samples/subsys/mgmt/mcumgr/smp_svr/src/main.c
@@ -83,7 +83,7 @@ static void advertise(void)
 static void connected(struct bt_conn *conn, u8_t err)
 {
 	if (err) {
-		printk("Connection failed (err %u)\n", err);
+		printk("Connection failed (err 0x%02x)\n", err);
 	} else {
 		printk("Connected\n");
 	}
@@ -91,7 +91,7 @@ static void connected(struct bt_conn *conn, u8_t err)
 
 static void disconnected(struct bt_conn *conn, u8_t reason)
 {
-	printk("Disconnected (reason %u)\n", reason);
+	printk("Disconnected (reason 0x%02x)\n", reason);
 	advertise();
 }
 
diff --git a/subsys/bluetooth/host/att.c b/subsys/bluetooth/host/att.c
index 1a81699b18..e28bf5fb78 100644
--- a/subsys/bluetooth/host/att.c
+++ b/subsys/bluetooth/host/att.c
@@ -349,7 +349,7 @@ static u8_t att_handle_rsp(struct bt_att *att, void *pdu, u16_t len, u8_t err)
 {
 	bt_att_func_t func;
 
-	BT_DBG("err %u len %u: %s", err, len, bt_hex(pdu, len));
+	BT_DBG("err 0x%02x len %u: %s", err, len, bt_hex(pdu, len));
 
 	/* Cancel timeout if ongoing */
 	k_delayed_work_cancel(&att->timeout_work);
diff --git a/subsys/bluetooth/host/hci_core.c b/subsys/bluetooth/host/hci_core.c
index 37c4a8853f..2bdffa6115 100644
--- a/subsys/bluetooth/host/hci_core.c
+++ b/subsys/bluetooth/host/hci_core.c
@@ -720,7 +720,7 @@ static void hci_disconn_complete(struct net_buf *buf)
 	u16_t handle = sys_le16_to_cpu(evt->handle);
 	struct bt_conn *conn;
 
-	BT_DBG("status %u handle %u reason %u", evt->status, handle,
+	BT_DBG("status 0x%02x handle %u reason 0x%02x", evt->status, handle,
 	       evt->reason);
 
 	if (evt->status) {
@@ -920,7 +920,7 @@ static void enh_conn_complete(struct bt_hci_evt_le_enh_conn_complete *evt)
 	struct bt_conn *conn;
 	int err;
 
-	BT_DBG("status %u handle %u role %u %s", evt->status, handle,
+	BT_DBG("status 0x%02x handle %u role %u %s", evt->status, handle,
 	       evt->role, bt_addr_le_str(&evt->peer_addr));
 
 #if defined(CONFIG_BT_SMP)
@@ -1115,7 +1115,7 @@ static void le_legacy_conn_complete(struct net_buf *buf)
 	struct bt_hci_evt_le_enh_conn_complete enh;
 	const bt_addr_le_t *id_addr;
 
-	BT_DBG("status %u role %u %s", evt->status, evt->role,
+	BT_DBG("status 0x%02x role %u %s", evt->status, evt->role,
 	       bt_addr_le_str(&evt->peer_addr));
 
 	enh.status         = evt->status;
@@ -1234,7 +1234,7 @@ static void le_phy_update_complete(struct net_buf *buf)
 		return;
 	}
 
-	BT_DBG("PHY updated: status: 0x%x, tx: %u, rx: %u",
+	BT_DBG("PHY updated: status: 0x%02x, tx: %u, rx: %u",
 	       evt->status, evt->tx_phy, evt->rx_phy);
 
 	if (!IS_ENABLED(CONFIG_BT_AUTO_PHY_UPDATE) ||
@@ -1359,7 +1359,7 @@ static void le_conn_update_complete(struct net_buf *buf)
 
 	handle = sys_le16_to_cpu(evt->handle);
 
-	BT_DBG("status %u, handle %u", evt->status, handle);
+	BT_DBG("status 0x%02x, handle %u", evt->status, handle);
 
 	conn = bt_conn_lookup_handle(handle);
 	if (!conn) {
@@ -2062,7 +2062,7 @@ static void ssp_complete(struct net_buf *buf)
 	struct bt_hci_evt_ssp_complete *evt = (void *)buf->data;
 	struct bt_conn *conn;
 
-	BT_DBG("status %u", evt->status);
+	BT_DBG("status 0x%02x", evt->status);
 
 	conn = bt_conn_lookup_addr_br(&evt->bdaddr);
 	if (!conn) {
@@ -2463,7 +2463,7 @@ static void auth_complete(struct net_buf *buf)
 	struct bt_conn *conn;
 	u16_t handle = sys_le16_to_cpu(evt->handle);
 
-	BT_DBG("status %u, handle %u", evt->status, handle);
+	BT_DBG("status 0x%02x, handle %u", evt->status, handle);
 
 	conn = bt_conn_lookup_handle(handle);
 	if (!conn) {
@@ -2494,7 +2494,7 @@ static void read_remote_features_complete(struct net_buf *buf)
 	struct bt_hci_cp_read_remote_ext_features *cp;
 	struct bt_conn *conn;
 
-	BT_DBG("status %u handle %u", evt->status, handle);
+	BT_DBG("status 0x%02x handle %u", evt->status, handle);
 
 	conn = bt_conn_lookup_handle(handle);
 	if (!conn) {
@@ -2535,7 +2535,7 @@ static void read_remote_ext_features_complete(struct net_buf *buf)
 	u16_t handle = sys_le16_to_cpu(evt->handle);
 	struct bt_conn *conn;
 
-	BT_DBG("status %u handle %u", evt->status, handle);
+	BT_DBG("status 0x%02x handle %u", evt->status, handle);
 
 	conn = bt_conn_lookup_handle(handle);
 	if (!conn) {
@@ -2556,7 +2556,7 @@ static void role_change(struct net_buf *buf)
 	struct bt_hci_evt_role_change *evt = (void *)buf->data;
 	struct bt_conn *conn;
 
-	BT_DBG("status %u role %u addr %s", evt->status, evt->role,
+	BT_DBG("status 0x%02x role %u addr %s", evt->status, evt->role,
 	       bt_addr_str(&evt->bdaddr));
 
 	if (evt->status) {
@@ -2877,7 +2877,7 @@ static void hci_encrypt_change(struct net_buf *buf)
 	u16_t handle = sys_le16_to_cpu(evt->handle);
 	struct bt_conn *conn;
 
-	BT_DBG("status %u handle %u encrypt 0x%02x", evt->status, handle,
+	BT_DBG("status 0x%02x handle %u encrypt 0x%02x", evt->status, handle,
 	       evt->encrypt);
 
 	conn = bt_conn_lookup_handle(handle);
@@ -2952,7 +2952,7 @@ static void hci_encrypt_key_refresh_complete(struct net_buf *buf)
 
 	handle = sys_le16_to_cpu(evt->handle);
 
-	BT_DBG("status %u handle %u", evt->status, handle);
+	BT_DBG("status 0x%02x handle %u", evt->status, handle);
 
 	conn = bt_conn_lookup_handle(handle);
 	if (!conn) {
@@ -3121,7 +3121,7 @@ static void le_pkey_complete(struct net_buf *buf)
 	struct bt_hci_evt_le_p256_public_key_complete *evt = (void *)buf->data;
 	struct bt_pub_key_cb *cb;
 
-	BT_DBG("status: 0x%x", evt->status);
+	BT_DBG("status: 0x%02x", evt->status);
 
 	atomic_clear_bit(bt_dev.flags, BT_DEV_PUB_KEY_BUSY);
 
@@ -3141,7 +3141,7 @@ static void le_dhkey_complete(struct net_buf *buf)
 {
 	struct bt_hci_evt_le_generate_dhkey_complete *evt = (void *)buf->data;
 
-	BT_DBG("status: 0x%x", evt->status);
+	BT_DBG("status: 0x%02x", evt->status);
 
 	if (dh_key_cb) {
 		dh_key_cb(evt->status ? NULL : evt->dhkey);
@@ -3155,7 +3155,7 @@ static void hci_reset_complete(struct net_buf *buf)
 	u8_t status = buf->data[0];
 	atomic_t flags;
 
-	BT_DBG("status %u", status);
+	BT_DBG("status 0x%02x", status);
 
 	if (status) {
 		return;
@@ -3730,7 +3730,7 @@ static void read_local_ver_complete(struct net_buf *buf)
 {
 	struct bt_hci_rp_read_local_version_info *rp = (void *)buf->data;
 
-	BT_DBG("status %u", rp->status);
+	BT_DBG("status 0x%02x", rp->status);
 
 	bt_dev.hci_version = rp->hci_version;
 	bt_dev.hci_revision = sys_le16_to_cpu(rp->hci_revision);
@@ -3743,7 +3743,7 @@ static void read_bdaddr_complete(struct net_buf *buf)
 {
 	struct bt_hci_rp_read_bd_addr *rp = (void *)buf->data;
 
-	BT_DBG("status %u", rp->status);
+	BT_DBG("status 0x%02x", rp->status);
 
 	if (!bt_addr_cmp(&rp->bdaddr, BT_ADDR_ANY) ||
 	    !bt_addr_cmp(&rp->bdaddr, BT_ADDR_NONE)) {
@@ -3760,7 +3760,7 @@ static void read_le_features_complete(struct net_buf *buf)
 {
 	struct bt_hci_rp_le_read_local_features *rp = (void *)buf->data;
 
-	BT_DBG("status %u", rp->status);
+	BT_DBG("status 0x%02x", rp->status);
 
 	memcpy(bt_dev.le.features, rp->features, sizeof(bt_dev.le.features));
 }
@@ -3771,7 +3771,7 @@ static void read_buffer_size_complete(struct net_buf *buf)
 	struct bt_hci_rp_read_buffer_size *rp = (void *)buf->data;
 	u16_t pkts;
 
-	BT_DBG("status %u", rp->status);
+	BT_DBG("status 0x%02x", rp->status);
 
 	bt_dev.br.mtu = sys_le16_to_cpu(rp->acl_max_len);
 	pkts = sys_le16_to_cpu(rp->acl_max_num);
@@ -3786,7 +3786,7 @@ static void read_buffer_size_complete(struct net_buf *buf)
 	struct bt_hci_rp_read_buffer_size *rp = (void *)buf->data;
 	u16_t pkts;
 
-	BT_DBG("status %u", rp->status);
+	BT_DBG("status 0x%02x", rp->status);
 
 	/* If LE-side has buffers we can ignore the BR/EDR values */
 	if (bt_dev.le.mtu) {
@@ -3810,7 +3810,7 @@ static void le_read_buffer_size_complete(struct net_buf *buf)
 	struct bt_hci_rp_le_read_buffer_size *rp = (void *)buf->data;
 	u8_t le_max_num;
 
-	BT_DBG("status %u", rp->status);
+	BT_DBG("status 0x%02x", rp->status);
 
 	bt_dev.le.mtu = sys_le16_to_cpu(rp->le_max_len);
 	if (!bt_dev.le.mtu) {
@@ -3828,7 +3828,7 @@ static void read_supported_commands_complete(struct net_buf *buf)
 {
 	struct bt_hci_rp_read_supported_commands *rp = (void *)buf->data;
 
-	BT_DBG("status %u", rp->status);
+	BT_DBG("status 0x%02x", rp->status);
 
 	memcpy(bt_dev.supported_commands, rp->commands,
 	       sizeof(bt_dev.supported_commands));
@@ -3847,7 +3847,7 @@ static void read_local_features_complete(struct net_buf *buf)
 {
 	struct bt_hci_rp_read_local_features *rp = (void *)buf->data;
 
-	BT_DBG("status %u", rp->status);
+	BT_DBG("status 0x%02x", rp->status);
 
 	memcpy(bt_dev.features[0], rp->features, sizeof(bt_dev.features[0]));
 }
@@ -3856,7 +3856,7 @@ static void le_read_supp_states_complete(struct net_buf *buf)
 {
 	struct bt_hci_rp_le_read_supp_states *rp = (void *)buf->data;
 
-	BT_DBG("status %u", rp->status);
+	BT_DBG("status 0x%02x", rp->status);
 
 	bt_dev.le.states = sys_get_le64(rp->le_states);
 }
diff --git a/subsys/bluetooth/shell/bt.c b/subsys/bluetooth/shell/bt.c
index b82f5f4279..25e019e1b5 100644
--- a/subsys/bluetooth/shell/bt.c
+++ b/subsys/bluetooth/shell/bt.c
@@ -172,7 +172,7 @@ static void disconnected(struct bt_conn *conn, u8_t reason)
 	char addr[BT_ADDR_LE_STR_LEN];
 
 	conn_addr_str(conn, addr, sizeof(addr));
-	shell_print(ctx_shell, "Disconnected: %s (reason %u)", addr, reason);
+	shell_print(ctx_shell, "Disconnected: %s (reason 0x%02x)", addr, reason);
 
 	if (default_conn == conn) {
 		bt_conn_unref(default_conn);
diff --git a/subsys/bluetooth/shell/gatt.c b/subsys/bluetooth/shell/gatt.c
index 41904e88a6..61ee17cde0 100644
--- a/subsys/bluetooth/shell/gatt.c
+++ b/subsys/bluetooth/shell/gatt.c
@@ -208,7 +208,7 @@ static u8_t read_func(struct bt_conn *conn, u8_t err,
 			 struct bt_gatt_read_params *params,
 			 const void *data, u16_t length)
 {
-	shell_print(ctx_shell, "Read complete: err %u length %u", err, length);
+	shell_print(ctx_shell, "Read complete: err 0x%02x length %u", err, length);
 
 	if (!data) {
 		(void)memset(params, 0, sizeof(*params));
@@ -324,7 +324,7 @@ static u8_t gatt_write_buf[CHAR_SIZE_MAX];
 static void write_func(struct bt_conn *conn, u8_t err,
 		       struct bt_gatt_write_params *params)
 {
-	shell_print(ctx_shell, "Write complete: err %u", err);
+	shell_print(ctx_shell, "Write complete: err 0x%02x", err);
 
 	(void)memset(&write_params, 0, sizeof(write_params));
 }
diff --git a/subsys/net/l2/bluetooth/bluetooth.c b/subsys/net/l2/bluetooth/bluetooth.c
index b9c277794f..1192ce4c64 100644
--- a/subsys/net/l2/bluetooth/bluetooth.c
+++ b/subsys/net/l2/bluetooth/bluetooth.c
@@ -586,7 +586,7 @@ static void disconnected(struct bt_conn *conn, u8_t reason)
 
 		bt_addr_le_to_str(bt_conn_get_dst(conn), addr, sizeof(addr));
 
-		NET_DBG("Disconnected: %s (reason %u)\n",
+		NET_DBG("Disconnected: %s (reason 0x%02x)\n",
 			log_strdup(addr), reason);
 	}
 
diff --git a/tests/bluetooth/bsim_bt/bsim_test_app/src/test_connect1.c b/tests/bluetooth/bsim_bt/bsim_test_app/src/test_connect1.c
index f260e91470..9705db1f40 100644
--- a/tests/bluetooth/bsim_bt/bsim_test_app/src/test_connect1.c
+++ b/tests/bluetooth/bsim_bt/bsim_test_app/src/test_connect1.c
@@ -337,7 +337,7 @@ static void disconnected(struct bt_conn *conn, u8_t reason)
 
 	bt_addr_le_to_str(bt_conn_get_dst(conn), addr, sizeof(addr));
 
-	printk("Disconnected: %s (reason %u)\n", addr, reason);
+	printk("Disconnected: %s (reason 0x%02x)\n", addr, reason);
 
 	if (default_conn != conn) {
 		return;
diff --git a/tests/bluetooth/bsim_bt/bsim_test_app/src/test_connect2.c b/tests/bluetooth/bsim_bt/bsim_test_app/src/test_connect2.c
index 384b20e768..fff8d593f0 100644
--- a/tests/bluetooth/bsim_bt/bsim_test_app/src/test_connect2.c
+++ b/tests/bluetooth/bsim_bt/bsim_test_app/src/test_connect2.c
@@ -77,7 +77,7 @@ static const struct bt_data ad[] = {
 static void connected(struct bt_conn *conn, u8_t err)
 {
 	if (err) {
-		FAIL("Connection failed (err %u)\n", err);
+		FAIL("Connection failed (err 0x%02x)\n", err);
 	} else {
 		default_conn = bt_conn_ref(conn);
 		printk("Connected\n");
@@ -86,7 +86,7 @@ static void connected(struct bt_conn *conn, u8_t err)
 
 static void disconnected(struct bt_conn *conn, u8_t reason)
 {
-	printk("Disconnected (reason %u)\n", reason);
+	printk("Disconnected (reason 0x%02x)\n", reason);
 
 	if (default_conn) {
 		bt_conn_unref(default_conn);