diff --git a/os/hal/platforms/STM32/OTGv1/usb_lld.c b/os/hal/platforms/STM32/OTGv1/usb_lld.c
index 78fc45a71..c0785a2e6 100644
--- a/os/hal/platforms/STM32/OTGv1/usb_lld.c
+++ b/os/hal/platforms/STM32/OTGv1/usb_lld.c
@@ -454,6 +454,12 @@ static void otg_txfifo_handler(USBDriver *usbp, usbep_t ep) {
   while (TRUE) {
     uint32_t n;
 
+    /* Interrupt disabled on transaction end.*/
+    if (usbp->epc[ep]->in_state->txcnt >= usbp->epc[ep]->in_state->txsize) {
+      OTG->DIEPEMPMSK &= ~DIEPEMPMSK_INEPTXFEM(ep);
+      return;
+    }
+
     /* Number of bytes remaining in current transaction.*/
     n = usbp->epc[ep]->in_state->txsize - usbp->epc[ep]->in_state->txcnt;
     if (n > usbp->epc[ep]->in_maxsize)
@@ -479,12 +485,6 @@ static void otg_txfifo_handler(USBDriver *usbp, usbep_t ep) {
       usbp->epc[ep]->in_state->mode.linear.txbuf += n;
     }
     usbp->epc[ep]->in_state->txcnt += n;
-
-    /* Interrupt disabled on transaction end.*/
-    if (usbp->epc[ep]->in_state->txcnt >= usbp->epc[ep]->in_state->txsize) {
-      OTG->DIEPEMPMSK &= ~DIEPEMPMSK_INEPTXFEM(ep);
-      return;
-    }
   }
 }
 
diff --git a/testhal/STM32F4xx/USB_CDC/main.c b/testhal/STM32F4xx/USB_CDC/main.c
index 7c033e7eb..4777f5c2a 100644
--- a/testhal/STM32F4xx/USB_CDC/main.c
+++ b/testhal/STM32F4xx/USB_CDC/main.c
@@ -395,7 +395,31 @@ static void cmd_test(BaseSequentialStream *chp, int argc, char *argv[]) {
 }
 
 static void cmd_usbblast(BaseSequentialStream *chp, int argc, char *argv[]) {
-  static uint8_t buf[512] =
+  static uint8_t buf[] =
+      "0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef"
+      "0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef"
+      "0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef"
+      "0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef"
+      "0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef"
+      "0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef"
+      "0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef"
+      "0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef"
+      "0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef"
+      "0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef"
+      "0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef"
+      "0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef"
+      "0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef"
+      "0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef"
+      "0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef"
+      "0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef"
+      "0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef"
+      "0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef"
+      "0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef"
+      "0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef"
+      "0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef"
+      "0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef"
+      "0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef"
+      "0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef"
       "0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef"
       "0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef"
       "0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef"
@@ -407,7 +431,7 @@ static void cmd_usbblast(BaseSequentialStream *chp, int argc, char *argv[]) {
 
   (void)argv;
   if (argc > 0) {
-    chprintf(chp, "Usage: test\r\n");
+    chprintf(chp, "Usage: usbblast\r\n");
     return;
   }