--- sys/src/cmd/usb/serial/prolific.c
+++ sys/src/cmd/usb/serial/prolific.c
@@ -411,19 +411,6 @@
 		;
 	fprint(2, "serial: statusreader exiting\n");
 	closedev(ser->dev);
-}
-
-/*
- * Maximum number of bytes transferred per frame
- * The output buffer size cannot be increased due to the size encoding
- */
-
-static int
-plseteps(Serialport *p)
-{
-	devctl(p->epin,  "maxpkt 256");
-	devctl(p->epout, "maxpkt 256");
-	return 0;
 }
 
 Serialops plops = {
@@ -434,5 +421,4 @@
 	.sendlines	= plsendlines,
 	.modemctl	= plmodemctl,
 	.setbreak	= plsetbreak,
-	.seteps		= plseteps,
 };