diff --git a/libfprint/drivers/aes1610.c b/libfprint/drivers/aes1610.c
index 0326565..4261b05 100644
--- a/libfprint/drivers/aes1610.c
+++ b/libfprint/drivers/aes1610.c
@@ -155,7 +155,6 @@ generic_read_ignore_data (FpiSsm *ssm, FpDevice *dev,
   transfer->short_is_error = TRUE;
   fpi_usb_transfer_submit (transfer, BULK_TIMEOUT, NULL,
                            generic_ignore_data_cb, NULL);
-  fpi_usb_transfer_unref (transfer);
 }
 
 /****** FINGER PRESENCE DETECTION ******/
@@ -238,7 +237,6 @@ finger_det_reqs_cb (FpImageDevice *dev, GError *error,
   transfer->short_is_error = TRUE;
   fpi_usb_transfer_submit (transfer, BULK_TIMEOUT, NULL,
                            finger_det_data_cb, NULL);
-  fpi_usb_transfer_unref (transfer);
 }
 
 static void
@@ -683,7 +681,6 @@ capture_run_state (FpiSsm *ssm, FpDevice *_dev)
       transfer->short_is_error = TRUE;
       fpi_usb_transfer_submit (transfer, BULK_TIMEOUT, NULL,
                                capture_read_strip_cb, NULL);
-      fpi_usb_transfer_unref (transfer);
       break;
     }
   ;
diff --git a/libfprint/drivers/aes2501.c b/libfprint/drivers/aes2501.c
index 1b59c56..e18b4fe 100644
--- a/libfprint/drivers/aes2501.c
+++ b/libfprint/drivers/aes2501.c
@@ -126,7 +126,6 @@ read_regs_rq_cb (FpImageDevice *dev, GError *error, void *user_data)
   fpi_usb_transfer_fill_bulk (transfer, EP_IN, READ_REGS_LEN);
   fpi_usb_transfer_submit (transfer, BULK_TIMEOUT, NULL,
                            read_regs_data_cb, rdata);
-  fpi_usb_transfer_unref (transfer);
 }
 
 static void
@@ -210,7 +209,6 @@ generic_read_ignore_data (FpiSsm *ssm, FpDevice *dev,
   fpi_usb_transfer_fill_bulk (transfer, EP_IN, bytes);
   fpi_usb_transfer_submit (transfer, BULK_TIMEOUT, NULL,
                            generic_ignore_data_cb, NULL);
-  fpi_usb_transfer_unref (transfer);
 }
 
 /****** IMAGE PROCESSING ******/
@@ -315,7 +313,6 @@ finger_det_reqs_cb (FpImageDevice *dev, GError *error,
   fpi_usb_transfer_fill_bulk (transfer, EP_IN, FINGER_DETECTION_LEN);
   fpi_usb_transfer_submit (transfer, BULK_TIMEOUT, NULL,
                            finger_det_data_cb, NULL);
-  fpi_usb_transfer_unref (transfer);
 }
 
 static void
@@ -547,7 +544,6 @@ capture_run_state (FpiSsm *ssm, FpDevice *device)
         fpi_usb_transfer_fill_bulk (transfer, EP_IN, STRIP_CAPTURE_LEN);
         fpi_usb_transfer_submit (transfer, BULK_TIMEOUT, NULL,
                                  capture_read_strip_cb, NULL);
-        fpi_usb_transfer_unref (transfer);
         break;
       }
     }
diff --git a/libfprint/drivers/aes2550.c b/libfprint/drivers/aes2550.c
index b95b053..f3f51d6 100644
--- a/libfprint/drivers/aes2550.c
+++ b/libfprint/drivers/aes2550.c
@@ -134,7 +134,6 @@ finger_det_reqs_cb (FpiUsbTransfer *t, FpDevice *device,
   fpi_usb_transfer_fill_bulk (transfer, EP_IN, AES2550_EP_IN_BUF_SIZE);
   fpi_usb_transfer_submit (transfer, BULK_TIMEOUT, NULL,
                            finger_det_data_cb, NULL);
-  fpi_usb_transfer_unref (transfer);
 }
 
 static void
@@ -157,7 +156,6 @@ start_finger_detection (FpImageDevice *dev)
                                    sizeof (finger_det_reqs), NULL);
   fpi_usb_transfer_submit (transfer, BULK_TIMEOUT, NULL,
                            finger_det_reqs_cb, NULL);
-  fpi_usb_transfer_unref (transfer);
 }
 
 /****** CAPTURE ******/
@@ -335,7 +333,6 @@ capture_run_state (FpiSsm *ssm, FpDevice *dev)
         transfer->short_is_error = TRUE;
         fpi_usb_transfer_submit (transfer, BULK_TIMEOUT, NULL,
                                  capture_reqs_cb, NULL);
-        fpi_usb_transfer_unref (transfer);
       }
       break;
 
@@ -347,7 +344,6 @@ capture_run_state (FpiSsm *ssm, FpDevice *dev)
         transfer->ssm = ssm;
         fpi_usb_transfer_submit (transfer, BULK_TIMEOUT, NULL,
                                  capture_read_data_cb, NULL);
-        fpi_usb_transfer_unref (transfer);
       }
       break;
 
@@ -363,7 +359,6 @@ capture_run_state (FpiSsm *ssm, FpDevice *dev)
         transfer->short_is_error = TRUE;
         fpi_usb_transfer_submit (transfer, BULK_TIMEOUT, NULL,
                                  capture_set_idle_reqs_cb, NULL);
-        fpi_usb_transfer_unref (transfer);
       }
       break;
     }
@@ -482,7 +477,6 @@ activate_run_state (FpiSsm *ssm, FpDevice *dev)
         transfer->short_is_error = TRUE;
         fpi_usb_transfer_submit (transfer, BULK_TIMEOUT, NULL,
                                  init_reqs_cb, NULL);
-        fpi_usb_transfer_unref (transfer);
       }
       break;
 
@@ -494,7 +488,6 @@ activate_run_state (FpiSsm *ssm, FpDevice *dev)
         transfer->ssm = ssm;
         fpi_usb_transfer_submit (transfer, BULK_TIMEOUT, NULL,
                                  init_read_data_cb, NULL);
-        fpi_usb_transfer_unref (transfer);
       }
       break;
 
@@ -509,7 +502,6 @@ activate_run_state (FpiSsm *ssm, FpDevice *dev)
         transfer->short_is_error = TRUE;
         fpi_usb_transfer_submit (transfer, BULK_TIMEOUT, NULL,
                                  init_reqs_cb, NULL);
-        fpi_usb_transfer_unref (transfer);
       }
       break;
 
@@ -521,7 +513,6 @@ activate_run_state (FpiSsm *ssm, FpDevice *dev)
         transfer->ssm = ssm;
         fpi_usb_transfer_submit (transfer, BULK_TIMEOUT, NULL,
                                  calibrate_read_data_cb, NULL);
-        fpi_usb_transfer_unref (transfer);
       }
       break;
     }
diff --git a/libfprint/drivers/aes3k.c b/libfprint/drivers/aes3k.c
index f73ac02..da3b6a3 100644
--- a/libfprint/drivers/aes3k.c
+++ b/libfprint/drivers/aes3k.c
@@ -142,7 +142,6 @@ do_capture (FpImageDevice *dev)
   fpi_usb_transfer_submit (priv->img_trf, 0,
                            fpi_device_get_cancellable (FP_DEVICE (dev)),
                            img_cb, NULL);
-  fpi_usb_transfer_unref (priv->img_trf);
 }
 
 static void
diff --git a/libfprint/drivers/aeslib.c b/libfprint/drivers/aeslib.c
index 8f92d87..4839c62 100644
--- a/libfprint/drivers/aeslib.c
+++ b/libfprint/drivers/aeslib.c
@@ -88,7 +88,6 @@ do_write_regv (FpImageDevice *dev, struct write_regv_data *wdata, int upper_boun
   transfer->short_is_error = TRUE;
   fpi_usb_transfer_submit (transfer, BULK_TIMEOUT, NULL,
                            write_regv_trf_complete, wdata);
-  fpi_usb_transfer_unref (transfer);
 }
 
 /* write the next batch of registers to be written, or if there are no more,
diff --git a/libfprint/drivers/aesx660.c b/libfprint/drivers/aesx660.c
index 3f13252..b4d8603 100644
--- a/libfprint/drivers/aesx660.c
+++ b/libfprint/drivers/aesx660.c
@@ -68,7 +68,6 @@ aesX660_send_cmd_timeout (FpiSsm                *ssm,
                                    cmd_len, NULL);
   transfer->ssm = ssm;
   fpi_usb_transfer_submit (transfer, timeout, NULL, callback, NULL);
-  fpi_usb_transfer_unref (transfer);
 }
 
 static void
@@ -100,7 +99,6 @@ aesX660_read_response (FpiSsm                *ssm,
   transfer->ssm = ssm;
   transfer->short_is_error = short_is_error;
   fpi_usb_transfer_submit (transfer, BULK_TIMEOUT, cancel, callback, NULL);
-  fpi_usb_transfer_unref (transfer);
 }
 
 static void
diff --git a/libfprint/drivers/elan.c b/libfprint/drivers/elan.c
index 5e80be5..e2767dd 100644
--- a/libfprint/drivers/elan.c
+++ b/libfprint/drivers/elan.c
@@ -406,7 +406,6 @@ elan_cmd_read (FpiSsm *ssm, FpDevice *dev)
     cancellable = fpi_device_get_cancellable (dev);
 
   fpi_usb_transfer_submit (transfer, self->cmd_timeout, cancellable, elan_cmd_cb, NULL);
-  fpi_usb_transfer_unref (transfer);
 }
 
 static void
@@ -449,7 +448,6 @@ elan_run_cmd (FpiSsm                *ssm,
                            cancellable,
                            elan_cmd_cb,
                            NULL);
-  fpi_usb_transfer_unref (transfer);
 }
 
 enum stop_capture_states {
diff --git a/libfprint/drivers/etes603.c b/libfprint/drivers/etes603.c
index 55f0139..5cd7f0b 100644
--- a/libfprint/drivers/etes603.c
+++ b/libfprint/drivers/etes603.c
@@ -710,7 +710,6 @@ async_tx (FpDevice *dev, unsigned int ep, void *cb,
   transfer->ssm = ssm;
   fpi_usb_transfer_fill_bulk_full (transfer, ep, buffer, length, NULL);
   fpi_usb_transfer_submit (transfer, BULK_TIMEOUT, NULL, cb, NULL);
-  fpi_usb_transfer_unref (transfer);
 }
 
 
diff --git a/libfprint/drivers/synaptics/synaptics.c b/libfprint/drivers/synaptics/synaptics.c
index 4932d01..ccaf60e 100644
--- a/libfprint/drivers/synaptics/synaptics.c
+++ b/libfprint/drivers/synaptics/synaptics.c
@@ -205,7 +205,7 @@ static void
 synaptics_cmd_run_state (FpiSsm   *ssm,
                          FpDevice *dev)
 {
-  g_autoptr(FpiUsbTransfer) transfer = NULL;
+  FpiUsbTransfer *transfer;
   FpiDeviceSynaptics *self = FPI_DEVICE_SYNAPTICS (dev);
 
   switch (fpi_ssm_get_cur_state (ssm))
@@ -219,7 +219,7 @@ synaptics_cmd_run_state (FpiSsm   *ssm,
                                    NULL,
                                    fpi_ssm_usb_transfer_cb,
                                    NULL);
-          g_clear_pointer (&self->cmd_pending_transfer, fpi_usb_transfer_unref);
+          self->cmd_pending_transfer = NULL;
         }
       else
         {
@@ -317,7 +317,7 @@ synaptics_sensor_cmd (FpiDeviceSynaptics *self,
                       gssize              payload_len,
                       SynCmdMsgCallback   callback)
 {
-  g_autoptr(FpiUsbTransfer) transfer = NULL;
+  FpiUsbTransfer *transfer;
   guint8 real_seq_num;
   gint msg_len;
   gint res;
@@ -984,7 +984,6 @@ dev_probe (FpDevice *device)
   transfer->buffer[0] = SENSOR_CMD_GET_VERSION;
   if (!fpi_usb_transfer_submit_sync (transfer, 1000, &error))
     goto err_close;
-  fpi_usb_transfer_unref (transfer);
 
 
   transfer = fpi_usb_transfer_new (device);
@@ -1039,7 +1038,6 @@ dev_probe (FpDevice *device)
   fp_dbg ("Target: %d", self->mis_version.target);
   fp_dbg ("Product: %d", self->mis_version.product);
 
-  fpi_usb_transfer_unref (transfer);
 
   /* We need at least firmware version 10.1, and for 10.1 build 2989158 */
   if (self->mis_version.version_major < 10 ||
diff --git a/libfprint/drivers/upeksonly.c b/libfprint/drivers/upeksonly.c
index e1cd7e5..f477b83 100644
--- a/libfprint/drivers/upeksonly.c
+++ b/libfprint/drivers/upeksonly.c
@@ -635,7 +635,6 @@ write_regs_iterate (struct write_regs_data *wrdata)
   transfer->short_is_error = TRUE;
   transfer->ssm = wrdata->ssm;
   fpi_usb_transfer_submit (transfer, CTRL_TIMEOUT, NULL, write_regs_cb, NULL);
-  fpi_usb_transfer_unref (transfer);
 
   transfer->buffer[0] = regwrite->value;
 }
@@ -688,7 +687,6 @@ sm_write_reg (FpiSsm        *ssm,
   transfer->short_is_error = TRUE;
   transfer->ssm = ssm;
   fpi_usb_transfer_submit (transfer, CTRL_TIMEOUT, NULL, sm_write_reg_cb, NULL);
-  fpi_usb_transfer_unref (transfer);
 
   transfer->buffer[0] = value;
 }
@@ -737,7 +735,6 @@ sm_read_reg (FpiSsm        *ssm,
                            NULL,
                            sm_read_reg_cb,
                            NULL);
-  fpi_usb_transfer_unref (transfer);
 }
 
 static void
@@ -782,7 +779,6 @@ sm_await_intr (FpiSsm        *ssm,
                            fpi_device_get_cancellable (FP_DEVICE (dev)),
                            sm_await_intr_cb,
                            NULL);
-  fpi_usb_transfer_unref (transfer);
 }
 
 /***** AWAIT FINGER *****/
@@ -1419,7 +1415,6 @@ dev_activate (FpImageDevice *dev)
   self->deactivating = FALSE;
   self->capturing = FALSE;
 
-  self->img_transfers = g_ptr_array_new_full (NUM_BULK_TRANSFERS, (GDestroyNotify) fpi_usb_transfer_unref);
   self->num_flying = 0;
 
   for (i = 0; i < self->img_transfers->len; i++)
diff --git a/libfprint/drivers/upektc.c b/libfprint/drivers/upektc.c
index e1254ce..92b1930 100644
--- a/libfprint/drivers/upektc.c
+++ b/libfprint/drivers/upektc.c
@@ -128,7 +128,6 @@ activate_run_state (FpiSsm *ssm, FpDevice *dev)
         transfer->short_is_error = TRUE;
         fpi_usb_transfer_submit (transfer, BULK_TIMEOUT, NULL,
                                  write_init_cb, NULL);
-        fpi_usb_transfer_unref (transfer);
       }
       break;
 
@@ -142,7 +141,6 @@ activate_run_state (FpiSsm *ssm, FpDevice *dev)
         transfer->ssm = ssm;
         fpi_usb_transfer_submit (transfer, BULK_TIMEOUT, NULL,
                                  read_init_data_cb, NULL);
-        fpi_usb_transfer_unref (transfer);
       }
       break;
     }
@@ -225,7 +223,6 @@ finger_det_cmd_cb (FpiUsbTransfer *t, FpDevice *device,
                               IMAGE_SIZE);
   fpi_usb_transfer_submit (transfer, BULK_TIMEOUT, NULL,
                            finger_det_data_cb, NULL);
-  fpi_usb_transfer_unref (transfer);
 }
 
 static void
@@ -249,7 +246,6 @@ start_finger_detection (FpImageDevice *dev)
                                    UPEKTC_CMD_LEN, NULL);
   fpi_usb_transfer_submit (transfer, BULK_TIMEOUT, NULL,
                            finger_det_cmd_cb, NULL);
-  fpi_usb_transfer_unref (transfer);
 }
 
 /****** CAPTURE ******/
@@ -309,7 +305,6 @@ capture_run_state (FpiSsm *ssm, FpDevice *_dev)
         transfer->short_is_error = TRUE;
         fpi_usb_transfer_submit (transfer, BULK_TIMEOUT, NULL,
                                  capture_cmd_cb, NULL);
-        fpi_usb_transfer_unref (transfer);
       }
       break;
 
@@ -323,7 +318,6 @@ capture_run_state (FpiSsm *ssm, FpDevice *_dev)
         transfer->short_is_error = TRUE;
         fpi_usb_transfer_submit (transfer, BULK_TIMEOUT, NULL,
                                  capture_read_data_cb, NULL);
-        fpi_usb_transfer_unref (transfer);
       }
       break;
     }
diff --git a/libfprint/drivers/upektc_img.c b/libfprint/drivers/upektc_img.c
index 28a709f..b9724c1 100644
--- a/libfprint/drivers/upektc_img.c
+++ b/libfprint/drivers/upektc_img.c
@@ -100,7 +100,6 @@ upektc_img_submit_req (FpiSsm                *ssm,
   transfer->ssm = ssm;
   transfer->short_is_error = TRUE;
   fpi_usb_transfer_submit (transfer, BULK_TIMEOUT, NULL, cb, NULL);
-  fpi_usb_transfer_unref (transfer);
 }
 
 static void
@@ -120,7 +119,6 @@ upektc_img_read_data (FpiSsm                *ssm,
                                    NULL);
   transfer->ssm = ssm;
   fpi_usb_transfer_submit (transfer, BULK_TIMEOUT, NULL, cb, NULL);
-  fpi_usb_transfer_unref (transfer);
 }
 
 /****** CAPTURE ******/
@@ -557,7 +555,6 @@ activate_run_state (FpiSsm *ssm, FpDevice *dev)
         transfer->ssm = ssm;
         fpi_usb_transfer_submit (transfer, CTRL_TIMEOUT, NULL,
                                  init_reqs_ctrl_cb, NULL);
-        fpi_usb_transfer_unref (transfer);
       }
       break;
 
diff --git a/libfprint/drivers/upekts.c b/libfprint/drivers/upekts.c
index 4bc6556..05cd9c5 100644
--- a/libfprint/drivers/upekts.c
+++ b/libfprint/drivers/upekts.c
@@ -226,7 +226,6 @@ busy_ack_retry_read (FpDevice *device, struct read_msg_data *udata)
   transfer->short_is_error = TRUE;
 
   fpi_usb_transfer_submit (transfer, TIMEOUT, NULL, busy_ack_sent_cb, udata);
-  fpi_usb_transfer_unref (transfer);
 }
 
 /* Returns 0 if message was handled, 1 if it was a device-busy message, and
@@ -416,7 +415,6 @@ read_msg_cb (FpiUsbTransfer *transfer, FpDevice *device,
       fpi_usb_transfer_submit (etransfer, TIMEOUT,
                                NULL,
                                read_msg_extend_cb, udata);
-      fpi_usb_transfer_unref (etransfer);
       return;
     }
 
@@ -442,7 +440,6 @@ __read_msg_async (FpDevice *device, struct read_msg_data *udata)
 
   fpi_usb_transfer_fill_bulk_full (transfer, EP_IN, udata->buffer, udata->buflen, NULL);
   fpi_usb_transfer_submit (transfer, TIMEOUT, NULL, read_msg_cb, udata);
-  fpi_usb_transfer_unref (transfer);
 }
 
 static void
@@ -676,7 +673,6 @@ initsm_send_msg28_handler (FpiSsm              *ssm,
   transfer->ssm = ssm;
   transfer->short_is_error = TRUE;
   fpi_usb_transfer_submit (transfer, TIMEOUT, NULL, fpi_ssm_usb_transfer_cb, NULL);
-  fpi_usb_transfer_unref (transfer);
 }
 
 static void
@@ -697,7 +693,6 @@ initsm_run_state (FpiSsm *ssm, FpDevice *dev)
       transfer->ssm = ssm;
       transfer->short_is_error = TRUE;
       fpi_usb_transfer_submit (transfer, TIMEOUT, NULL, fpi_ssm_usb_transfer_cb, NULL);
-      fpi_usb_transfer_unref (transfer);
       break;
 
     case READ_MSG03:
@@ -709,7 +704,6 @@ initsm_run_state (FpiSsm *ssm, FpDevice *dev)
       transfer->ssm = ssm;
       transfer->short_is_error = TRUE;
       fpi_usb_transfer_submit (transfer, TIMEOUT, NULL, fpi_ssm_usb_transfer_cb, NULL);
-      fpi_usb_transfer_unref (transfer);
       break;
 
     case READ_MSG05:
@@ -820,7 +814,6 @@ deinitsm_state_handler (FpiSsm *ssm, FpDevice *dev)
       transfer->short_is_error = TRUE;
       transfer->ssm = ssm;
       fpi_usb_transfer_submit (transfer, TIMEOUT, NULL, fpi_ssm_usb_transfer_cb, NULL);
-      fpi_usb_transfer_unref (transfer);
       break;
 
     case READ_MSG01:;
@@ -953,7 +946,6 @@ enroll_start_sm_run_state (FpiSsm *ssm, FpDevice *dev)
       transfer->ssm = ssm;
 
       fpi_usb_transfer_submit (transfer, TIMEOUT, NULL, fpi_ssm_usb_transfer_cb, NULL);
-      fpi_usb_transfer_unref (transfer);
       break;
 
     case READ_ENROLL_MSG28:;
@@ -1205,7 +1197,6 @@ enroll_iterate (FpDevice *dev)
   transfer->short_is_error = TRUE;
 
   fpi_usb_transfer_submit (transfer, TIMEOUT, NULL, enroll_iterate_cmd_cb, NULL);
-  fpi_usb_transfer_unref (transfer);
 }
 
 static void
@@ -1319,7 +1310,6 @@ verify_start_sm_run_state (FpiSsm *ssm, FpDevice *dev)
       transfer->short_is_error = TRUE;
       transfer->ssm = ssm;
       fpi_usb_transfer_submit (transfer, TIMEOUT, NULL, fpi_ssm_usb_transfer_cb, NULL);
-      fpi_usb_transfer_unref (transfer);
 
       break;
     }
@@ -1519,7 +1509,6 @@ verify_iterate (FpDevice *dev)
       transfer->short_is_error = TRUE;
 
       fpi_usb_transfer_submit (transfer, TIMEOUT, NULL, verify_wr2800_cb, NULL);
-      fpi_usb_transfer_unref (transfer);
     }
 }
 
diff --git a/libfprint/drivers/uru4000.c b/libfprint/drivers/uru4000.c
index 89328d0..7e28724 100644
--- a/libfprint/drivers/uru4000.c
+++ b/libfprint/drivers/uru4000.c
@@ -181,7 +181,6 @@ write_regs (FpImageDevice *dev, uint16_t first_reg,
                                  num_regs);
   memcpy (transfer->buffer, values, num_regs);
   fpi_usb_transfer_submit (transfer, CTRL_TIMEOUT, NULL, callback, user_data);
-  fpi_usb_transfer_unref (transfer);
 }
 
 static void
@@ -207,7 +206,6 @@ read_regs (FpImageDevice *dev, uint16_t first_reg,
                                  G_USB_DEVICE_RECIPIENT_DEVICE,
                                  USB_RQ, first_reg, 0, num_regs);
   fpi_usb_transfer_submit (transfer, CTRL_TIMEOUT, NULL, callback, user_data);
-  fpi_usb_transfer_unref (transfer);
 }
 
 /*
@@ -365,7 +363,6 @@ start_irq_handler (FpImageDevice *dev)
                               EP_INTR,
                               IRQ_LENGTH);
   fpi_usb_transfer_submit (transfer, 0, self->irq_cancellable, irq_handler, NULL);
-  fpi_usb_transfer_unref (transfer);
 }
 
 static void
diff --git a/libfprint/drivers/vcom5s.c b/libfprint/drivers/vcom5s.c
index edd2dd4..1a2b795 100644
--- a/libfprint/drivers/vcom5s.c
+++ b/libfprint/drivers/vcom5s.c
@@ -103,7 +103,6 @@ sm_write_reg (FpiSsm       *ssm,
   transfer->ssm = ssm;
   fpi_usb_transfer_submit (transfer, CTRL_TIMEOUT, NULL, sm_write_reg_cb,
                            NULL);
-  fpi_usb_transfer_unref (transfer);
 }
 
 static void
@@ -133,7 +132,6 @@ sm_exec_cmd (FpiSsm       *ssm,
   transfer->ssm = ssm;
   fpi_usb_transfer_submit (transfer, CTRL_TIMEOUT, NULL, sm_exec_cmd_cb,
                            NULL);
-  fpi_usb_transfer_unref (transfer);
 }
 
 /***** FINGER DETECTION *****/
@@ -227,7 +225,6 @@ capture_iterate (FpiSsm   *ssm,
                                    NULL);
 
   fpi_usb_transfer_submit (transfer, CTRL_TIMEOUT, NULL, capture_cb, NULL);
-  fpi_usb_transfer_unref (transfer);
 }
 
 
diff --git a/libfprint/drivers/vfs0050.c b/libfprint/drivers/vfs0050.c
index 1be272b..43252c0 100644
--- a/libfprint/drivers/vfs0050.c
+++ b/libfprint/drivers/vfs0050.c
@@ -56,7 +56,6 @@ async_write (FpiSsm   *ssm,
   transfer->short_is_error = TRUE;
   fpi_usb_transfer_submit (transfer, VFS_USB_TIMEOUT, NULL,
                            async_write_callback, NULL);
-  fpi_usb_transfer_unref (transfer);
 }
 
 /* Callback for async_read */
@@ -108,7 +107,6 @@ async_read (FpiSsm   *ssm,
 
   fpi_usb_transfer_submit (transfer, VFS_USB_TIMEOUT, NULL,
                            async_read_callback, NULL);
-  fpi_usb_transfer_unref (transfer);
 }
 
 /* Callback for async_abort */
@@ -160,7 +158,6 @@ async_abort (FpDevice *dev, FpiSsm *ssm, int ep)
 
   fpi_usb_transfer_submit (transfer, VFS_USB_ABORT_TIMEOUT, NULL,
                            async_abort_callback, NULL);
-  fpi_usb_transfer_unref (transfer);
 }
 
 /* Image processing functions */
@@ -564,7 +561,6 @@ activate_ssm (FpiSsm *ssm, FpDevice *dev)
                                  0,
                                  fpi_device_get_cancellable (dev),
                                  interrupt_callback, NULL);
-        fpi_usb_transfer_unref (transfer);
 
         /* I've put it here to be sure that data is cleared */
         clear_data (self);
@@ -614,7 +610,6 @@ activate_ssm (FpiSsm *ssm, FpDevice *dev)
         transfer->ssm = ssm;
         fpi_usb_transfer_submit (transfer, VFS_USB_TIMEOUT, NULL,
                                  receive_callback, NULL);
-        fpi_usb_transfer_unref (transfer);
         break;
       }
 
diff --git a/libfprint/drivers/vfs101.c b/libfprint/drivers/vfs101.c
index 9ca1b0a..5dedab7 100644
--- a/libfprint/drivers/vfs101.c
+++ b/libfprint/drivers/vfs101.c
@@ -219,7 +219,6 @@ async_send (FpiSsm        *ssm,
   transfer->short_is_error = TRUE;
   fpi_usb_transfer_submit (transfer, BULK_TIMEOUT, NULL,
                            async_send_cb, NULL);
-  fpi_usb_transfer_unref (transfer);
 }
 
 /* Callback of asynchronous recv */
@@ -282,7 +281,6 @@ async_recv (FpiSsm        *ssm,
   transfer->ssm = ssm;
   fpi_usb_transfer_submit (transfer, BULK_TIMEOUT, NULL,
                            async_recv_cb, NULL);
-  fpi_usb_transfer_unref (transfer);
 }
 
 static void async_load (FpiSsm        *ssm,
@@ -369,7 +367,6 @@ async_load (FpiSsm        *ssm,
   transfer->ssm = ssm;
   fpi_usb_transfer_submit (transfer, BULK_TIMEOUT, NULL,
                            async_load_cb, NULL);
-  fpi_usb_transfer_unref (transfer);
 }
 
 /* Submit asynchronous sleep */
diff --git a/libfprint/drivers/vfs301_proto.c b/libfprint/drivers/vfs301_proto.c
index 5d02597..103e890 100644
--- a/libfprint/drivers/vfs301_proto.c
+++ b/libfprint/drivers/vfs301_proto.c
@@ -67,8 +67,7 @@ static void
 usb_recv (FpDeviceVfs301 *dev, guint8 endpoint, int max_bytes, FpiUsbTransfer **out, GError **error)
 {
   GError *err = NULL;
-
-  g_autoptr(FpiUsbTransfer) transfer = NULL;
+  FpiUsbTransfer *transfer;
 
   /* XXX: This function swallows any transfer errors, that is obviously
    *      quite bad (it used to assert on no-error)! */
@@ -98,8 +97,7 @@ static void
 usb_send (FpDeviceVfs301 *dev, const guint8 *data, gssize length, GError **error)
 {
   GError *err = NULL;
-
-  g_autoptr(FpiUsbTransfer) transfer = NULL;
+  FpiUsbTransfer *transfer = NULL;
 
   /* XXX: This function swallows any transfer errors, that is obviously
    *      quite bad (it used to assert on no-error)! */
@@ -471,7 +469,7 @@ int
 vfs301_proto_peek_event (FpDeviceVfs301 *dev)
 {
   g_autoptr(GError) error = NULL;
-  g_autoptr(FpiUsbTransfer) transfer = NULL;
+  FpiUsbTransfer *transfer;
 
   const char no_event[] = {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00};
   const char got_event[] = {0x00, 0x00, 0x02, 0x00, 0x00, 0x00, 0x00};
@@ -540,7 +538,6 @@ vfs301_proto_process_event_cb (FpiUsbTransfer *transfer,
       fpi_usb_transfer_fill_bulk (new, VFS301_RECEIVE_ENDPOINT_DATA, VFS301_FP_RECV_LEN_2);
       fpi_usb_transfer_submit (new, VFS301_FP_RECV_TIMEOUT, NULL,
                                vfs301_proto_process_event_cb, NULL);
-      fpi_usb_transfer_unref (new);
       return;
     }
 }
@@ -580,7 +577,6 @@ vfs301_proto_process_event_start (FpDeviceVfs301 *dev)
   fpi_usb_transfer_fill_bulk (transfer, VFS301_RECEIVE_ENDPOINT_DATA, VFS301_FP_RECV_LEN_1);
   fpi_usb_transfer_submit (transfer, VFS301_FP_RECV_TIMEOUT, NULL,
                            vfs301_proto_process_event_cb, NULL);
-  fpi_usb_transfer_unref (transfer);
 }
 
 int
diff --git a/libfprint/drivers/vfs5011.c b/libfprint/drivers/vfs5011.c
index 007e486..dbf8276 100644
--- a/libfprint/drivers/vfs5011.c
+++ b/libfprint/drivers/vfs5011.c
@@ -168,7 +168,6 @@ usbexchange_loop (FpiSsm *ssm, FpDevice *_dev)
       transfer->short_is_error = TRUE;
       fpi_usb_transfer_submit (transfer, data->timeout, NULL,
                                async_send_cb, NULL);
-      fpi_usb_transfer_unref (transfer);
       break;
 
     case ACTION_RECEIVE:
@@ -180,7 +179,6 @@ usbexchange_loop (FpiSsm *ssm, FpDevice *_dev)
       transfer->ssm = ssm;
       fpi_usb_transfer_submit (transfer, data->timeout, NULL,
                                async_recv_cb, NULL);
-      fpi_usb_transfer_unref (transfer);
       break;
 
     default:
@@ -466,7 +464,6 @@ capture_chunk_async (FpDeviceVfs5011 *self,
   transfer->ssm = ssm;
   fpi_usb_transfer_submit (transfer, timeout, fpi_device_get_cancellable (FP_DEVICE (self)),
                            chunk_capture_callback, NULL);
-  fpi_usb_transfer_unref (transfer);
 }
 
 /*
diff --git a/libfprint/fpi-usb-transfer.c b/libfprint/fpi-usb-transfer.c
index 6b29621..64d706f 100644
--- a/libfprint/fpi-usb-transfer.c
+++ b/libfprint/fpi-usb-transfer.c
@@ -356,7 +356,7 @@ transfer_finish_cb (GObject *source_object, GAsyncResult *res, gpointer user_dat
 
 /**
  * fpi_usb_transfer_submit:
- * @transfer: The transfer to submit, must have been filled.
+ * @transfer: (transfer full): The transfer to submit, must have been filled.
  * @timeout_ms: Timeout for the transfer in ms
  * @cancellable: Cancellable to use, e.g. fpi_device_get_cancellable()
  * @callback: Callback on completion or error
@@ -364,10 +364,9 @@ transfer_finish_cb (GObject *source_object, GAsyncResult *res, gpointer user_dat
  *
  * Submit a USB transfer with a specific timeout and callback functions.
  *
- * Note that #FpiUsbTransfer is owned by the user. In most cases, you
- * should call fpi_usb_transfer_unref() just after calling this function.
- * Doing so means that all associated data will be free'ed automatically
- * after the callback ran.
+ * Note that #FpiUsbTransfer will be stolen when this function is called.
+ * So that all associated data will be free'ed automatically, after the
+ * callback ran unless fpi_usb_transfer_ref() is explictly called.
  */
 void
 fpi_usb_transfer_submit (FpiUsbTransfer        *transfer,
@@ -385,11 +384,6 @@ fpi_usb_transfer_submit (FpiUsbTransfer        *transfer,
   transfer->callback = callback;
   transfer->user_data = user_data;
 
-  /* Grab a reference, this means that one can simply unref after submit and
-   * trust for the data to disappear without explicit management by the callback
-   * function. */
-  fpi_usb_transfer_ref (transfer);
-
   log_transfer (transfer, TRUE, NULL);
 
   switch (transfer->type)