diff --git a/build-gpudemod-dll.ps1 b/build-gpudemod-dll.ps1
index 47f021c..7108a5c 100644
--- a/build-gpudemod-dll.ps1
+++ b/build-gpudemod-dll.ps1
@@ -17,7 +17,7 @@ if (!(Test-Path $outDir)) { New-Item -ItemType Directory -Path $outDir | Out-Nul
 Remove-Item $dll,$lib,$exp -Force -ErrorAction SilentlyContinue
 
 $cmd = @"
-call "$vcvars" && "$nvcc" -shared "$src" -o "$dll" -Xcompiler "/MD" -arch=sm_75 -gencode arch=compute_75,code=sm_75 -gencode arch=compute_80,code=sm_80 -gencode arch=compute_86,code=sm_86 -gencode arch=compute_89,code=sm_89 -gencode arch=compute_90,code=sm_90
+call "$vcvars" && "$nvcc" -shared "$src" -o "$dll" -cudart=shared -Xcompiler "/MD" -arch=sm_75 -gencode arch=compute_75,code=sm_75 -gencode arch=compute_80,code=sm_80 -gencode arch=compute_86,code=sm_86 -gencode arch=compute_89,code=sm_89 -gencode arch=compute_90,code=sm_90
 "@
 
 Write-Host 'Building gpudemod CUDA DLL...' -ForegroundColor Cyan
diff --git a/build-sdrplay.ps1 b/build-sdrplay.ps1
index a884df9..d20c89a 100644
--- a/build-sdrplay.ps1
+++ b/build-sdrplay.ps1
@@ -40,7 +40,11 @@ $dllDst = Join-Path $PSScriptRoot 'gpudemod_kernels.dll'
 $dllSrc = $dllCandidates | Where-Object { Test-Path $_ } | Select-Object -First 1
 if ($dllSrc) {
   if ((Resolve-Path $dllSrc).Path -ne (Resolve-Path (Split-Path $dllDst -Parent)).Path + '\gpudemod_kernels.dll') {
-    Copy-Item $dllSrc $dllDst -Force
+    try {
+      Copy-Item $dllSrc $dllDst -Force
+    } catch {
+      Write-Host "WARNING: could not refresh runtime DLL at $dllDst ($($_.Exception.Message))" -ForegroundColor Yellow
+    }
   }
   Write-Host "CUDA DLL ready at $dllDst" -ForegroundColor Green
 } else {
diff --git a/cmd/sdrd/dsp_loop.go b/cmd/sdrd/dsp_loop.go
index 76a5989..8d5e9ad 100644
--- a/cmd/sdrd/dsp_loop.go
+++ b/cmd/sdrd/dsp_loop.go
@@ -195,7 +195,7 @@ func runDSP(ctx context.Context, srcMgr *sourceManager, cfg config.Config, det *
 			if rec != nil && len(finished) > 0 {
 				evCopy := make([]detector.Event, len(finished))
 				copy(evCopy, finished)
-				go rec.OnEvents(evCopy)
+				rec.OnEvents(evCopy)
 			}
 			var debugInfo *SpectrumDebug
 			if len(thresholds) > 0 || len(signals) > 0 || noiseFloor != 0 {
diff --git a/internal/demod/gpudemod/gpudemod_windows.go b/internal/demod/gpudemod/gpudemod_windows.go
index 5e17e0b..feda60d 100644
--- a/internal/demod/gpudemod/gpudemod_windows.go
+++ b/internal/demod/gpudemod/gpudemod_windows.go
@@ -405,7 +405,6 @@ func (e *Engine) Demod(iq []complex64, offsetHz float64, bw float64, mode DemodT
 		return nil, 0, errors.New("sample count exceeds engine capacity")
 	}
 
-	_ = fmt.Sprintf("%s:%0.3f", phaseStatus(), offsetHz)
 	shifted, ok := e.tryCUDAFreqShift(iq, offsetHz)
 	e.lastShiftUsedGPU = ok && ValidateFreqShift(iq, e.sampleRate, offsetHz, shifted, 1e-3)
 	if !e.lastShiftUsedGPU {
diff --git a/internal/recorder/recorder.go b/internal/recorder/recorder.go
index 6b7b8d4..411f2f8 100644
--- a/internal/recorder/recorder.go
+++ b/internal/recorder/recorder.go
@@ -6,6 +6,7 @@ import (
 	"os"
 	"path/filepath"
 	"strings"
+	"sync"
 	"time"
 
 	"sdr-visual-suite/internal/demod/gpudemod"
@@ -29,6 +30,7 @@ type Policy struct {
 }
 
 type Manager struct {
+	mu             sync.RWMutex
 	policy         Policy
 	ring           *Ring
 	sampleRate     int
@@ -53,12 +55,14 @@ func New(sampleRate int, blockSize int, policy Policy, centerHz float64, decodeC
 }
 
 func (m *Manager) Update(sampleRate int, blockSize int, policy Policy, centerHz float64, decodeCommands map[string]string) {
+	m.mu.Lock()
+	defer m.mu.Unlock()
 	m.policy = policy
 	m.sampleRate = sampleRate
 	m.blockSize = blockSize
 	m.centerHz = centerHz
 	m.decodeCommands = decodeCommands
-	m.initGPUDemod(sampleRate, blockSize)
+	m.initGPUDemodLocked(sampleRate, blockSize)
 	if m.ring == nil {
 		m.ring = NewRing(sampleRate, blockSize, policy.RingSeconds)
 		return
@@ -67,14 +71,26 @@ func (m *Manager) Update(sampleRate int, blockSize int, policy Policy, centerHz
 }
 
 func (m *Manager) Ingest(t0 time.Time, samples []complex64) {
-	if m == nil || m.ring == nil {
+	if m == nil {
+		return
+	}
+	m.mu.RLock()
+	ring := m.ring
+	m.mu.RUnlock()
+	if ring == nil {
 		return
 	}
-	m.ring.Push(t0, samples)
+	ring.Push(t0, samples)
 }
 
 func (m *Manager) OnEvents(events []detector.Event) {
-	if m == nil || !m.policy.Enabled || len(events) == 0 {
+	if m == nil || len(events) == 0 {
+		return
+	}
+	m.mu.RLock()
+	enabled := m.policy.Enabled
+	m.mu.RUnlock()
+	if !enabled {
 		return
 	}
 	for _, ev := range events {
@@ -93,6 +109,12 @@ func (m *Manager) worker() {
 }
 
 func (m *Manager) initGPUDemod(sampleRate int, blockSize int) {
+	m.mu.Lock()
+	defer m.mu.Unlock()
+	m.initGPUDemodLocked(sampleRate, blockSize)
+}
+
+func (m *Manager) initGPUDemodLocked(sampleRate int, blockSize int) {
 	if m.gpuDemod != nil {
 		m.gpuDemod.Close()
 		m.gpuDemod = nil
@@ -108,22 +130,29 @@ func (m *Manager) initGPUDemod(sampleRate int, blockSize int) {
 }
 
 func (m *Manager) recordEvent(ev detector.Event) error {
-	if !m.policy.Enabled {
+	m.mu.RLock()
+	policy := m.policy
+	ring := m.ring
+	sampleRate := m.sampleRate
+	centerHz := m.centerHz
+	m.mu.RUnlock()
+
+	if !policy.Enabled {
 		return nil
 	}
-	if ev.SNRDb < m.policy.MinSNRDb {
+	if ev.SNRDb < policy.MinSNRDb {
 		return nil
 	}
 	dur := ev.End.Sub(ev.Start)
-	if m.policy.MinDuration > 0 && dur < m.policy.MinDuration {
+	if policy.MinDuration > 0 && dur < policy.MinDuration {
 		return nil
 	}
-	if m.policy.MaxDuration > 0 && dur > m.policy.MaxDuration {
+	if policy.MaxDuration > 0 && dur > policy.MaxDuration {
 		return nil
 	}
-	if len(m.policy.ClassFilter) > 0 && ev.Class != nil {
+	if len(policy.ClassFilter) > 0 && ev.Class != nil {
 		match := false
-		for _, c := range m.policy.ClassFilter {
+		for _, c := range policy.ClassFilter {
 			if strings.EqualFold(c, string(ev.Class.ModType)) {
 				match = true
 				break
@@ -133,46 +162,49 @@ func (m *Manager) recordEvent(ev detector.Event) error {
 			return nil
 		}
 	}
-	if !m.policy.RecordIQ && !m.policy.RecordAudio {
+	if !policy.RecordIQ && !policy.RecordAudio {
 		return nil
 	}
 
-	start := ev.Start.Add(-time.Duration(m.policy.PrerollMs) * time.Millisecond)
+	start := ev.Start.Add(-time.Duration(policy.PrerollMs) * time.Millisecond)
 	end := ev.End
 	if start.After(end) {
 		return errors.New("invalid event window")
 	}
+	if ring == nil {
+		return errors.New("no ring buffer")
+	}
 
-	segment := m.ring.Slice(start, end)
+	segment := ring.Slice(start, end)
 	if len(segment) == 0 {
 		return errors.New("no iq in ring")
 	}
 
-	dir := filepath.Join(m.policy.OutputDir, fmt.Sprintf("%s_%0.fHz_evt%d", ev.Start.Format("2006-01-02T15-04-05"), ev.CenterHz, ev.ID))
+	dir := filepath.Join(policy.OutputDir, fmt.Sprintf("%s_%0.fHz_evt%d", ev.Start.Format("2006-01-02T15-04-05"), ev.CenterHz, ev.ID))
 	if err := os.MkdirAll(dir, 0o755); err != nil {
 		return err
 	}
 	files := map[string]any{}
 	var iqPath string
-	if m.policy.RecordIQ {
+	if policy.RecordIQ {
 		iqPath = filepath.Join(dir, "signal.cf32")
 		if err := writeCF32(iqPath, segment); err != nil {
 			return err
 		}
 		files["iq"] = "signal.cf32"
 		files["iq_format"] = "cf32"
-		files["iq_sample_rate"] = m.sampleRate
+		files["iq_sample_rate"] = sampleRate
 	}
 
-	// Optional demod + audio
-	if m.policy.RecordAudio && m.policy.AutoDemod && ev.Class != nil {
+	if policy.RecordAudio && policy.AutoDemod && ev.Class != nil {
 		if err := m.demodAndWrite(dir, ev, segment, files); err != nil {
 			return err
 		}
 	}
-	if m.policy.AutoDecode && iqPath != "" && ev.Class != nil {
-		m.runDecodeIfConfigured(string(ev.Class.ModType), iqPath, m.sampleRate, files, dir)
+	if policy.AutoDecode && iqPath != "" && ev.Class != nil {
+		m.runDecodeIfConfigured(string(ev.Class.ModType), iqPath, sampleRate, files, dir)
 	}
 
-	return writeMeta(dir, ev, m.sampleRate, files)
+	_ = centerHz
+	return writeMeta(dir, ev, sampleRate, files)
 }