diff --git a/src/stm32/usbfs.c b/src/stm32/usbfs.c
index 661aa1b1..d166fbb7 100644
--- a/src/stm32/usbfs.c
+++ b/src/stm32/usbfs.c
@@ -118,8 +118,8 @@ btable_configure(void)
     epm_ep_desc_setup(USB_CDC_EP_ACM, BUFRX, 0);
     epm_ep_desc_setup(USB_CDC_EP_BULK_OUT, 0, USB_CDC_EP_BULK_OUT_SIZE);
     epm_ep_desc_setup(USB_CDC_EP_BULK_OUT, 1, USB_CDC_EP_BULK_OUT_SIZE);
-    epm_ep_desc_setup(USB_CDC_EP_BULK_IN, BUFTX, 0);
-    epm_ep_desc_setup(USB_CDC_EP_BULK_IN, BUFRX, 0);
+    epm_ep_desc_setup(USB_CDC_EP_BULK_IN, 0, 0);
+    epm_ep_desc_setup(USB_CDC_EP_BULK_IN, 1, 0);
 }
 
 // Read a packet stored in dedicated usb memory
@@ -236,15 +236,27 @@ usb_read_bulk_out(void *data, uint_fast8_t max_len)
     return count;
 }
 
+static uint32_t bulk_in_push_count, bulk_in_pop_flag;
+
 int_fast8_t
 usb_send_bulk_in(void *data, uint_fast8_t len)
 {
-    uint32_t ep = USB_CDC_EP_BULK_IN, epr = USB_EPR[ep];
-    if ((epr & USB_EPTX_STAT) != USB_EP_TX_NAK)
+    if (readl(&bulk_in_pop_flag))
         // No buffer space available
         return -1;
-    btable_write_packet(ep, BUFTX, data, len);
-    USB_EPR[ep] = calc_epr_bits(epr, USB_EPTX_STAT, USB_EP_TX_VALID);
+    uint32_t ep = USB_CDC_EP_BULK_IN;
+    int bufnum = bulk_in_push_count & 1;
+    bulk_in_push_count++;
+    btable_write_packet(ep, bufnum, data, len);
+    writel(&bulk_in_pop_flag, USB_EP_DTOG_RX);
+
+    // Check if hardware needs to be notified
+    uint32_t epr = USB_EPR[ep];
+    if (epr_is_dbuf_blocking(epr) && readl(&bulk_in_pop_flag)) {
+        writel(&bulk_in_pop_flag, 0);
+        USB_EPR[ep] = calc_epr_bits(epr, 0, 0) | USB_EP_DTOG_RX;
+    }
+
     return len;
 }
 
@@ -305,6 +317,11 @@ usb_set_configure(void)
     uint32_t ep = USB_CDC_EP_BULK_OUT;
     bulk_out_pop_count = 0;
     USB_EPR[ep] = calc_epr_bits(USB_EPR[ep], USB_EPRX_STAT, USB_EP_RX_VALID);
+
+    ep = USB_CDC_EP_BULK_IN;
+    bulk_in_push_count = 0;
+    writel(&bulk_in_pop_flag, 0);
+    USB_EPR[ep] = calc_epr_bits(USB_EPR[ep], USB_EPTX_STAT, USB_EP_TX_VALID);
 }
 
 
@@ -329,8 +346,9 @@ usb_reset(void)
     bulk_out_push_flag = USB_EP_DTOG_TX;
 
     ep = USB_CDC_EP_BULK_IN;
-    USB_EPR[ep] = (USB_CDC_EP_BULK_IN | USB_EP_BULK
+    USB_EPR[ep] = (USB_CDC_EP_BULK_IN | USB_EP_BULK | USB_EP_KIND
                    | USB_EP_RX_NAK | USB_EP_TX_NAK);
+    bulk_in_pop_flag = USB_EP_DTOG_RX;
 
     USB->CNTR = USB_CNTR_CTRM | USB_CNTR_RESETM;
     USB->DADDR = USB_DADDR_EF;
@@ -350,7 +368,9 @@ USB_IRQHandler(void)
             bulk_out_push_flag = 0;
             usb_notify_bulk_out();
         } else if (ep == USB_CDC_EP_BULK_IN) {
-            USB_EPR[ep] = calc_epr_bits(epr, USB_EP_CTR_RX | USB_EP_CTR_TX, 0);
+            USB_EPR[ep] = (calc_epr_bits(epr, USB_EP_CTR_RX | USB_EP_CTR_TX, 0)
+                           | bulk_in_pop_flag);
+            bulk_in_pop_flag = 0;
             usb_notify_bulk_in();
         } else if (ep == 0) {
             USB_EPR[ep] = calc_epr_bits(epr, USB_EP_CTR_RX | USB_EP_CTR_TX, 0);