diff --git a/ngc_ft1.cpp b/ngc_ft1.cpp
index 28f4f02..a59d250 100644
--- a/ngc_ft1.cpp
+++ b/ngc_ft1.cpp
@@ -262,7 +262,7 @@ void NGC_FT1_iterate(Tox *tox, NGC_FT1* ngc_ft1_ctx) {
 								while (tf.ssb.size() < 1) {
 									std::vector<uint8_t> new_data;
 
-									size_t chunk_size = std::min<size_t>(10u, tf.file_size - tf.file_size_current);
+									size_t chunk_size = std::min<size_t>(400u, tf.file_size - tf.file_size_current);
 									if (chunk_size == 0) {
 										// TODO: set to finishing?
 										break; // we done
@@ -811,6 +811,8 @@ static void _handle_FT1_DATA_ACK(
 		return;
 	}
 
+	transfer.time_since_activity = 0.f;
+
 	while (curser < length) {
 		uint16_t seq_id = data[curser++];
 		seq_id |= data[curser++] << (1*8);