diff --git a/README.md b/README.md
index 5dca521..1df21b4 100644
--- a/README.md
+++ b/README.md
@@ -54,9 +54,7 @@ $ tox_ngc_ft1_tool
  FT1:
  --ft_ack_per_packet
  --ft_init_retry_timeout_after
- --ft_sending_resend_without_ack_after
  --ft_sending_give_up_after
- --ft_packet_window_size
 
  transfer logic:
  -I <max_incoming_transfers>
diff --git a/external/tox_ngc_ft1/tox_ngc_ft1 b/external/tox_ngc_ft1/tox_ngc_ft1
index e1b5dd2..95bfa24 160000
--- a/external/tox_ngc_ft1/tox_ngc_ft1
+++ b/external/tox_ngc_ft1/tox_ngc_ft1
@@ -1 +1 @@
-Subproject commit e1b5dd20804503668572edf15ef1b2db2b1847b3
+Subproject commit 95bfa2473c30c8a43e29199621398f1d4bb76ef4
diff --git a/src/command_line.cpp b/src/command_line.cpp
index 78dc29f..970a125 100644
--- a/src/command_line.cpp
+++ b/src/command_line.cpp
@@ -119,9 +119,7 @@ CommandLine::CommandLine(int argc, char** argv) {
 			std::cout << "CL set tox_port to " << tox_port << "\n";
 		} else if (parser.parseParam("--ft_ack_per_packet", ft_acks_per_packet)) {
 		} else if (parser.parseParam("--ft_init_retry_timeout_after", ft_init_retry_timeout_after)) {
-		} else if (parser.parseParam("--ft_sending_resend_without_ack_after", ft_sending_resend_without_ack_after)) {
 		} else if (parser.parseParam("--ft_sending_give_up_after", ft_sending_give_up_after)) {
-		} else if (parser.parseParam("--ft_packet_window_size", ft_packet_window_size)) {
 		} else if (parser.parseParam("-I", max_incoming_transfers)) {
 		} else if (parser.parseParam("-O", max_outgoing_transfers)) {
 		} else {
diff --git a/src/command_line.hpp b/src/command_line.hpp
index 1c92a4f..a7118b2 100644
--- a/src/command_line.hpp
+++ b/src/command_line.hpp
@@ -60,12 +60,8 @@ struct CommandLine {
 	size_t ft_acks_per_packet {3};
 	// --ft_init_retry_timeout_after
 	float ft_init_retry_timeout_after {5.f};
-	// --ft_sending_resend_without_ack_after
-	float ft_sending_resend_without_ack_after {3.f};
 	// --ft_sending_give_up_after
 	float ft_sending_give_up_after {30.f};
-	// --ft_packet_window_size
-	size_t ft_packet_window_size {8};
 
 	// ---- TODO ----
 
diff --git a/src/states/sha1.cpp b/src/states/sha1.cpp
index d12f94d..b0414da 100644
--- a/src/states/sha1.cpp
+++ b/src/states/sha1.cpp
@@ -168,6 +168,10 @@ bool SHA1::iterate(float delta) {
 			const auto [group_number, peer_number, chunk_hash, _] = _queue_requested_chunk.front();
 
 			if (_tcl.getGroupPeerConnectionStatus(group_number, peer_number) != TOX_CONNECTION_NONE) {
+				if (!chunkIndex(chunk_hash).has_value()) {
+					std::cerr << "!chunkIndex(chunk_hash).has_value()\n";
+					exit(1);
+				}
 				size_t chunk_index = chunkIndex(chunk_hash).value();
 				size_t chunk_file_size = chunkSize(chunk_index);
 
diff --git a/src/tox_client.cpp b/src/tox_client.cpp
index 8e132ea..64be7cf 100644
--- a/src/tox_client.cpp
+++ b/src/tox_client.cpp
@@ -124,9 +124,7 @@ ToxClient::ToxClient(const CommandLine& cl) :
 	NGC_FT1_options ft1_options {};
 	ft1_options.acks_per_packet = cl.ft_acks_per_packet;
 	ft1_options.init_retry_timeout_after = cl.ft_init_retry_timeout_after;
-	ft1_options.sending_resend_without_ack_after = cl.ft_sending_resend_without_ack_after;
 	ft1_options.sending_give_up_after = cl.ft_sending_give_up_after;
-	ft1_options.packet_window_size = cl.ft_packet_window_size;
 	_ft1_ctx = NGC_FT1_new(&ft1_options);
 	NGC_FT1_register_ext(_ft1_ctx, _ext_ctx);