diff --git a/src/_h5ai/conf/options.json b/src/_h5ai/conf/options.json
index deb35704..fc70051b 100644
--- a/src/_h5ai/conf/options.json
+++ b/src/_h5ai/conf/options.json
@@ -105,7 +105,7 @@ Options
 	*/
 	"download": {
 		"enabled": true,
-		"execution": "shell",
+		"execution": "php",
 		"format": "tar",
 		"packageName": null
 	},
diff --git a/src/_h5ai/server/php/inc/Api.php b/src/_h5ai/server/php/inc/Api.php
index 63a3ed7d..327f3ef9 100644
--- a/src/_h5ai/server/php/inc/Api.php
+++ b/src/_h5ai/server/php/inc/Api.php
@@ -136,21 +136,18 @@ class Api {
 			header("Connection: close");
 			register_shutdown_function("delete_tempfile", $target);
 
-			readfile($target);
+			// readfile($target);
 
-			// Patch by Zhao Lei
-			// Max size of download file is limited by memory_limit(default: 128M)
-			// in php.ini if we use readfile().
-			// To solve this problem, we can change to send data with small segments.
-			// if ($fd = fopen($target, 'rb')) {
-			// 	set_time_limit(0);
-			// 	while (!feof($fd)) {
-			// 		print fread($fd, 1024 * 64);
-			// 		ob_flush();
-			// 		flush();
-			// 	}
-			// 	fclose($fd);
-			// }
+			// Send data in small segments of 16MB to not hit PHP's memory limit (default: 128M)
+			if ($fd = fopen($target, 'rb')) {
+				set_time_limit(0);
+				while (!feof($fd)) {
+					print fread($fd, 1024 * 1024 * 16);
+					ob_flush();
+					flush();
+				}
+				fclose($fd);
+			}
 		}