diff --git a/firmware/apps/dfu/main.c b/firmware/apps/dfu/main.c
index 48138818..48ba879c 100644
--- a/firmware/apps/dfu/main.c
+++ b/firmware/apps/dfu/main.c
@@ -342,7 +342,7 @@ extern int main(void)
 	TRACE_INFO("USB init...\n\r");
 	/* Signal USB reset by disabling the pull-up on USB D+ for at least 10 ms */
 	USBD_Disconnect();
-	mdelay(50);
+	mdelay(500);
 	USBDFU_Initialize(&dfu_descriptors);
 
 	while (USBD_GetState() < USBD_STATE_CONFIGURED) {
diff --git a/firmware/libcommon/source/usb.c b/firmware/libcommon/source/usb.c
index 08682638..d86fc923 100644
--- a/firmware/libcommon/source/usb.c
+++ b/firmware/libcommon/source/usb.c
@@ -690,7 +690,7 @@ void SIMtrace_USB_Initialize(void)
 	unsigned int i;
 	/* Signal USB reset by disabling the pull-up on USB D+ for at least 10 ms */
 	USBD_HAL_Suspend();
-	mdelay(20);
+	mdelay(500);
 	USBD_HAL_Activate();
 
 	// Get std USB driver