diff --git a/firmware/application/main.cpp b/firmware/application/main.cpp
index 432ed932..4239708e 100755
--- a/firmware/application/main.cpp
+++ b/firmware/application/main.cpp
@@ -28,6 +28,9 @@
 //TEST: Check AFSK transmit end, skips last bits ?
 //TEST: Imperial in whipcalc
 
+//BUG: CPLD-related rx ok, tx bad, see portapack.cpp lines 214+ to disable CPLD overlay
+//BUG: REPLAY See what's wrong with quality (format, or need for interpolation filter ?)
+//TODO: REPLAY Convert C16 to C8 on M0 core
 //BUG: SCANNER Lock on frequency, if frequency jump, still locked on first one
 //BUG: SCANNER Multiple slices
 //BUG: REPLAY freezes when SD card not present
diff --git a/firmware/application/replay_thread.cpp b/firmware/application/replay_thread.cpp
index 67fec113..0942a58d 100644
--- a/firmware/application/replay_thread.cpp
+++ b/firmware/application/replay_thread.cpp
@@ -25,10 +25,6 @@
 #include "baseband_api.hpp"
 #include "buffer_exchange.hpp"
 
-// DEBUG:
-#include "hackrf_gpio.hpp"
-using namespace hackrf::one;
-
 struct BasebandReplay {
 	BasebandReplay(ReplayConfig* const config) {
 		baseband::replay_start(config);
@@ -90,10 +86,7 @@ Optional<File::Error> ReplayThread::run() {
 			return read_result.error();
 		}
 		
-		if (!buffers.put(buffer))
-			for(;;){};		// DEBUG
-		
-		led_tx.toggle();	// DEBUG
+		buffers.put(buffer);
 	}
 
 	return { };
diff --git a/firmware/application/ui_replay_view.cpp b/firmware/application/ui_replay_view.cpp
index 1c274c08..87cc2218 100644
--- a/firmware/application/ui_replay_view.cpp
+++ b/firmware/application/ui_replay_view.cpp
@@ -91,7 +91,7 @@ void ReplayView::set_file_list(const std::vector<std::filesystem::path>& file_li
 	
 	for (const auto& file : file_list) {
 		bbd_file.open("/" + file.string());
-		duration = bbd_file.size() / (2 * 2 * (sampling_rate / 8));
+		duration = bbd_file.size() / (2 * 2 * sampling_rate / 4);
 		file_options.emplace_back(file.string().substr(0, 8), duration);
 	}
 	options_files.set_options(file_options);
diff --git a/firmware/application/ui_replay_view.hpp b/firmware/application/ui_replay_view.hpp
index 3f708a60..607ea862 100644
--- a/firmware/application/ui_replay_view.hpp
+++ b/firmware/application/ui_replay_view.hpp
@@ -59,7 +59,7 @@ private:
 	using option_t = std::pair<std::string, int32_t>;
 	using options_t = std::vector<option_t>;
 	
-	static constexpr uint32_t sampling_rate = 1000000;
+	static constexpr uint32_t sampling_rate = 4000000;
 	
 	void toggle();
 
diff --git a/firmware/baseband/proc_replay.cpp b/firmware/baseband/proc_replay.cpp
index ce6e0315..601af9ac 100644
--- a/firmware/baseband/proc_replay.cpp
+++ b/firmware/baseband/proc_replay.cpp
@@ -27,26 +27,40 @@
 #include "utility.hpp"
 
 ReplayProcessor::ReplayProcessor() {
+	// TODO: Interpolation filter needed !
+	
+	/*spectrum_interval_samples = baseband_fs / spectrum_rate_hz;
+	spectrum_samples = 0;
 
+	channel_spectrum.set_decimation_factor(1);*/
+	
 }
 
 void ReplayProcessor::execute(const buffer_c8_t& buffer) {
-	/* 2.4576MHz, 2048 samples */
+	/* 4MHz, 2048 samples */
 
 	size_t pos = 0;
 	
-	for (size_t c = 0; c < 4; c++) {
-		if( stream ) {
-			const size_t bytes_to_read = sizeof(*buffer.p) * buffer.count / 4;
-			const auto result = stream->read(iq_buffer.p, bytes_to_read);
-		}
+	// File data is in C16 format, we need C8
+	// File samplerate is 500kHz, we're at 4MHz
+	// iq_buffer can only be 512 samples (RAM limitation)
+	// For a full 2048-sample C8 buffer, we need:
+	// 2048 samples * 2 bytes per sample = 4096 bytes
+	// Since we're oversampling by 4M/500k = 8, we only need 2048/8 = 256 samples from the file
+	// So 256 * 4 bytes per sample (C16) = 1024 bytes from the file
+	if( stream ) {
+		const size_t bytes_to_read = sizeof(*buffer.p) * 2 * (buffer.count / 8);	// *2 (C16), /8 (oversampling)
+		const auto result = stream->read(iq_buffer.p, bytes_to_read);
+	}
 
-		//feed_channel_stats(channel);
-		
-		for (size_t i = 0; i < (buffer.count / 4); i++) {
-			buffer.p[pos] = { iq_buffer.p[i].real() >> 8, iq_buffer.p[i].imag() >> 8 };
-			pos++;
-		}
+	//feed_channel_stats(channel);
+	
+	// Zero-stuff
+	for (size_t i = 0; i < buffer.count; i++) {
+		if (i & 3)
+			buffer.p[i] = { 0, 0 };
+		else
+			buffer.p[i] = { iq_buffer.p[i >> 3].real() >> 8, iq_buffer.p[i >> 3].imag() >> 8 };
 	}
 	
 	/*spectrum_samples += channel.count;
diff --git a/firmware/baseband/proc_replay.hpp b/firmware/baseband/proc_replay.hpp
index 34c20d8b..ebf7e69f 100644
--- a/firmware/baseband/proc_replay.hpp
+++ b/firmware/baseband/proc_replay.hpp
@@ -26,6 +26,8 @@
 #include "baseband_processor.hpp"
 #include "baseband_thread.hpp"
 
+#include "spectrum_collector.hpp"
+
 #include "stream_output.hpp"
 
 #include <array>
@@ -40,14 +42,12 @@ public:
 	void on_message(const Message* const message) override;
 
 private:
-	// TODO: Repeated value needs to be transmitted from application side.
-	static constexpr size_t baseband_fs = 1000000;
+	static constexpr size_t baseband_fs = 4000000;
 	//static constexpr auto spectrum_rate_hz = 50.0f;
 
 	BasebandThread baseband_thread { baseband_fs, this, NORMALPRIO + 20, baseband::Direction::Transmit };
-	//RSSIThread rssi_thread { NORMALPRIO + 10 };
 
-	std::array<complex16_t, 512> iq { };	// 2048 doesn't fit in allocated RAM
+	std::array<complex16_t, 256> iq { };	// This fits in just right in allocated RAM
 	const buffer_c16_t iq_buffer {
 		iq.data(),
 		iq.size()