diff --git a/go_backend/metadata.go b/go_backend/metadata.go
index a6daa4bc..3001730e 100644
--- a/go_backend/metadata.go
+++ b/go_backend/metadata.go
@@ -498,7 +498,7 @@ func EmbedM4AMetadata(filePath string, metadata Metadata, coverData []byte) erro
 	}
 
 	// Find udta atom inside moov, or create one
-	moovSize := int(data[moovPos]<<24 | data[moovPos+1]<<16 | data[moovPos+2]<<8 | data[moovPos+3])
+	moovSize := int(uint32(data[moovPos])<<24 | uint32(data[moovPos+1])<<16 | uint32(data[moovPos+2])<<8 | uint32(data[moovPos+3]))
 	udtaPos := findAtom(data, "udta", moovPos+8)
 
 	// Build new metadata atoms
@@ -507,12 +507,12 @@ func EmbedM4AMetadata(filePath string, metadata Metadata, coverData []byte) erro
 	var newData []byte
 	if udtaPos >= 0 && udtaPos < moovPos+moovSize {
 		// udta exists, find meta inside it or replace
-		udtaSize := int(data[udtaPos]<<24 | data[udtaPos+1]<<16 | data[udtaPos+2]<<8 | data[udtaPos+3])
+		udtaSize := int(uint32(data[udtaPos])<<24 | uint32(data[udtaPos+1])<<16 | uint32(data[udtaPos+2])<<8 | uint32(data[udtaPos+3]))
 		metaPos := findAtom(data, "meta", udtaPos+8)
 
 		if metaPos >= 0 && metaPos < udtaPos+udtaSize {
 			// Replace existing meta atom
-			metaSize := int(data[metaPos]<<24 | data[metaPos+1]<<16 | data[metaPos+2]<<8 | data[metaPos+3])
+			metaSize := int(uint32(data[metaPos])<<24 | uint32(data[metaPos+1])<<16 | uint32(data[metaPos+2])<<8 | uint32(data[metaPos+3]))
 			newData = append(newData, data[:metaPos]...)
 			newData = append(newData, metaAtom...)
 			newData = append(newData, data[metaPos+metaSize:]...)
@@ -570,7 +570,7 @@ func EmbedM4AMetadata(filePath string, metadata Metadata, coverData []byte) erro
 // findAtom finds an atom by name starting from offset
 func findAtom(data []byte, name string, offset int) int {
 	for i := offset; i < len(data)-8; {
-		size := int(data[i]<<24 | data[i+1]<<16 | data[i+2]<<8 | data[i+3])
+		size := int(uint32(data[i])<<24 | uint32(data[i+1])<<16 | uint32(data[i+2])<<8 | uint32(data[i+3]))
 		if size < 8 {
 			break
 		}
diff --git a/go_backend/qobuz.go b/go_backend/qobuz.go
index 198b6262..923f1ed3 100644
--- a/go_backend/qobuz.go
+++ b/go_backend/qobuz.go
@@ -819,77 +819,6 @@ func getQobuzDownloadURLParallel(apis []string, trackID int64, quality string) (
 	return "", "", fmt.Errorf("all %d Qobuz APIs failed. Errors: %v", len(apis), errors)
 }
 
-// getQobuzDownloadURLSequential requests download URL from APIs sequentially
-// Uses same URL format as PC version: /api/stream?trackId={id}&quality={quality}
-func getQobuzDownloadURLSequential(apis []string, trackID int64, quality string) (string, string, error) {
-	if len(apis) == 0 {
-		return "", "", fmt.Errorf("no APIs available")
-	}
-
-	client := NewHTTPClientWithTimeout(DefaultTimeout)
-	retryConfig := DefaultRetryConfig()
-	var errors []string
-
-	for _, apiURL := range apis {
-		// All APIs now use same format: https://domain/api/stream?trackId={id}&quality={quality}
-		// The apiURL already includes the path, just append trackID and quality
-		reqURL := fmt.Sprintf("%s%d&quality=%s", apiURL, trackID, quality)
-
-		GoLog("[Qobuz] Trying: %s\n", reqURL)
-
-		req, err := http.NewRequest("GET", reqURL, nil)
-		if err != nil {
-			errors = append(errors, BuildErrorMessage(apiURL, 0, err.Error()))
-			continue
-		}
-
-		resp, err := DoRequestWithRetry(client, req, retryConfig)
-		if err != nil {
-			errors = append(errors, BuildErrorMessage(apiURL, 0, err.Error()))
-			continue
-		}
-
-		body, err := ReadResponseBody(resp)
-		resp.Body.Close()
-		if err != nil {
-			errors = append(errors, BuildErrorMessage(apiURL, resp.StatusCode, err.Error()))
-			continue
-		}
-
-		// Check if response is HTML (error page)
-		if len(body) > 0 && body[0] == '<' {
-			errors = append(errors, BuildErrorMessage(apiURL, resp.StatusCode, "received HTML instead of JSON"))
-			continue
-		}
-
-		// Check for error in JSON response
-		var errorResp struct {
-			Error string `json:"error"`
-		}
-		if json.Unmarshal(body, &errorResp) == nil && errorResp.Error != "" {
-			errors = append(errors, BuildErrorMessage(apiURL, resp.StatusCode, errorResp.Error))
-			continue
-		}
-
-		var result struct {
-			URL string `json:"url"`
-		}
-		if err := json.Unmarshal(body, &result); err != nil {
-			errors = append(errors, BuildErrorMessage(apiURL, resp.StatusCode, "invalid JSON: "+err.Error()))
-			continue
-		}
-
-		if result.URL != "" {
-			GoLog("[Qobuz] Got download URL from: %s\n", apiURL)
-			return apiURL, result.URL, nil
-		}
-
-		errors = append(errors, BuildErrorMessage(apiURL, resp.StatusCode, "no download URL in response"))
-	}
-
-	return "", "", fmt.Errorf("all %d Qobuz APIs failed. Errors: %v", len(apis), errors)
-}
-
 // GetDownloadURL gets download URL for a track - tries ALL APIs in parallel
 // "Siapa cepat dia dapat" - first successful response wins
 func (q *QobuzDownloader) GetDownloadURL(trackID int64, quality string) (string, error) {