diff --git a/main.cpp b/main.cpp
index 03819eb..6f7c0b1 100644
--- a/main.cpp
+++ b/main.cpp
@@ -761,6 +761,17 @@ Config parse_args(int argc, char** argv) {
             cfg.input_buffer_words = std::max<uint32_t>(cfg.input_buffer_words, 16U * 1024U * 1024U);
         }
     }
+    if (cfg.do1_toggle_per_frame) {
+        if (!cfg.recv_block_specified) {
+            cfg.recv_block_words = 1024U;
+        }
+        if (!cfg.input_step_specified) {
+            cfg.input_step_words = 1024U;
+        }
+        if (!cfg.input_buffer_specified) {
+            cfg.input_buffer_words = std::max<uint32_t>(cfg.input_buffer_words, 256U * 1024U);
+        }
+    }
     if (cfg.recv_block_words == 0) {
         fail("recv_block must be > 0");
     }
@@ -1573,6 +1584,7 @@ int run(const Config& cfg) {
     TickMs last_stats_print = capture_loop_start;
     TickMs last_live_update = 0;
     bool do1_next_state_high = false;
+    bool do1_last_queued_high = false;
     const std::size_t max_pending_dout_words = 1000000U;
     std::vector<uint32_t> dout_prepare_input;
     std::vector<uint32_t> dout_send_words;
@@ -1930,6 +1942,9 @@ int run(const Config& cfg) {
 
         uint32_t recv_request_words = cfg.recv_block_words;
         uint32_t recv_timeout_ms = cfg.recv_timeout_ms;
+        if (cfg.do1_toggle_per_frame) {
+            recv_timeout_ms = std::min<uint32_t>(recv_timeout_ms, 1U);
+        }
         uint32_t ready_words = 0;
         const int32_t ready_err = api.GetRecvReadyCount(device.hnd, &ready_words);
         if ((ready_err == X502_ERR_OK) && (ready_words != 0U)) {
@@ -2150,9 +2165,6 @@ int run(const Config& cfg) {
 
             if (packet_active && stop_edge) {
                 finish_packet(PacketCloseReason::ExternalStopEdge);
-                if (cfg.do1_toggle_per_frame && (lch == (cfg.channel_count - 1U))) {
-                    append_dout_word(false);
-                }
                 if ((cfg.packet_limit != 0U) && (total_completed_packets >= cfg.packet_limit)) {
                     stop_loop_requested = true;
                 }
@@ -2162,9 +2174,11 @@ int run(const Config& cfg) {
             if (cfg.do1_toggle_per_frame && (lch == (cfg.channel_count - 1U))) {
                 if (packet_active) {
                     append_dout_word(do1_next_state_high);
+                    do1_last_queued_high = do1_next_state_high;
                     do1_next_state_high = !do1_next_state_high;
-                } else {
+                } else if (do1_last_queued_high) {
                     append_dout_word(false);
+                    do1_last_queued_high = false;
                 }
             }
 
@@ -2238,7 +2252,9 @@ int run(const Config& cfg) {
             }
         }
 
-        flush_dout_queue(0U, false);
+        const uint32_t dout_send_timeout_ms =
+            cfg.do1_toggle_per_frame ? std::min<uint32_t>(cfg.recv_timeout_ms, 1U) : 0U;
+        flush_dout_queue(dout_send_timeout_ms, false);
         flush_tty_frames();
 
         if (console_stop_requested()) {