diff --git a/inc/usb.h b/inc/usb.h
index 1145b00..24e1731 100644
--- a/inc/usb.h
+++ b/inc/usb.h
@@ -44,6 +44,9 @@ bool_t ep_tx_ready(uint8_t ep);
  * REQUIRES: ep_tx_ready(@ep) == TRUE */
 void usb_write(uint8_t ep, const void *buf, uint32_t len);
 
+/* Is the USB enumerated at High Speed? */
+bool_t usb_is_highspeed(void);
+
 /*
  * Local variables:
  * mode: C
diff --git a/src/floppy.c b/src/floppy.c
index 2e96d59..1fe8a5a 100644
--- a/src/floppy.c
+++ b/src/floppy.c
@@ -615,10 +615,15 @@ static uint8_t floppy_write_prep(const struct gw_write_flux *wf)
 static void floppy_write_wait_data(void)
 {
     bool_t write_finished;
+    unsigned int u_buf_threshold;
 
     floppy_process_write_packet();
     wdata_decode_flux();
 
+    /* We don't wait for the massive F7 u_buf[] to fill at Full Speed. */
+    u_buf_threshold = ((U_BUF_SZ > 16384) && !usb_is_highspeed())
+        ? 16384 - 512 : U_BUF_SZ - 512;
+
     /* Wait for DMA and input buffers to fill, or write stream to end. We must
      * take care because, since we are not yet draining the DMA buffer, the
      * write stream may end without us noticing and setting rw.write_finished. 
@@ -627,7 +632,7 @@ static void floppy_write_wait_data(void)
                       ? rw.write_finished
                       : (u_buf[U_MASK(u_prod-1)] == 0));
     if (((dma.prod != (ARRAY_SIZE(dma.buf)-1)) 
-         || ((uint32_t)(u_prod - u_cons) < (U_BUF_SZ - 512)))
+         || ((uint32_t)(u_prod - u_cons) < u_buf_threshold))
         && !write_finished)
         return;
 
diff --git a/src/usb/core.c b/src/usb/core.c
index 4615b1d..e1f3fad 100644
--- a/src/usb/core.c
+++ b/src/usb/core.c
@@ -49,7 +49,7 @@ static bool_t handle_control_request(void)
                 memcpy(ep0.data, device_qualifier, ep0.data_len);
             }
         } else if ((type == DESC_CONFIGURATION) && (idx == 0)) {
-            if (hw_is_highspeed()) {
+            if (usb_is_highspeed()) {
                 ep0.data_len = config_hs_descriptor[2]; /* wTotalLength */
                 memcpy(ep0.data, config_hs_descriptor, ep0.data_len);
             } else {
diff --git a/src/usb/defs.h b/src/usb/defs.h
index 0fb6d63..497f06c 100644
--- a/src/usb/defs.h
+++ b/src/usb/defs.h
@@ -83,7 +83,6 @@ void usb_setaddr(uint8_t addr);
 void hw_usb_init(void);
 void hw_usb_deinit(void);
 bool_t hw_has_highspeed(void);
-bool_t hw_is_highspeed(void);
 
 #define WARN printk
 
diff --git a/src/usb/hw_dwc_otg.c b/src/usb/hw_dwc_otg.c
index ffe871f..a9b8847 100644
--- a/src/usb/hw_dwc_otg.c
+++ b/src/usb/hw_dwc_otg.c
@@ -31,7 +31,7 @@ bool_t hw_has_highspeed(void)
     return conf_iface == IFACE_HS_EMBEDDED;
 }
 
-bool_t hw_is_highspeed(void)
+bool_t usb_is_highspeed(void)
 {
     return is_hs;
 }
diff --git a/src/usb/hw_f1.c b/src/usb/hw_f1.c
index 7b4e455..0619d18 100644
--- a/src/usb/hw_f1.c
+++ b/src/usb/hw_f1.c
@@ -27,7 +27,7 @@ bool_t hw_has_highspeed(void)
     return FALSE;
 }
 
-bool_t hw_is_highspeed(void)
+bool_t usb_is_highspeed(void)
 {
     return FALSE;
 }