From 8e21d5cba0efcf06ccf5e4d387a0bea0e06e6689 Mon Sep 17 00:00:00 2001
From: Mike Walters <mike@flomp.net>
Date: Sat, 30 Jul 2016 10:57:32 +0100
Subject: [PATCH] Skip first block after retune

---
 firmware/hackrf_usb/usb_api_sweep.c | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/firmware/hackrf_usb/usb_api_sweep.c b/firmware/hackrf_usb/usb_api_sweep.c
index 1a7ad97c..6ae5a2e9 100644
--- a/firmware/hackrf_usb/usb_api_sweep.c
+++ b/firmware/hackrf_usb/usb_api_sweep.c
@@ -93,12 +93,13 @@ void sweep_mode(void) {
 		if (transfer) {
 			*(uint16_t*)buffer = 0x7F7F;
 			*(uint16_t*)(buffer+2) = sweep_freq;
-			usb_transfer_schedule_block(
-				&usb_endpoint_bulk_in,
-				buffer,
-				0x4000,
-				NULL, NULL
-			);
+			if (blocks_queued > 1)
+				usb_transfer_schedule_block(
+					&usb_endpoint_bulk_in,
+					buffer,
+					0x4000,
+					NULL, NULL
+				);
 			transfer = false;
 		}