From 112b7fec537b85121e9ba530070d2e1642bc556b Mon Sep 17 00:00:00 2001
From: Michael Loukeris <loukerismichalis@gmail.com>
Date: Wed, 14 Oct 2026 01:51:34 +0300
Subject: [PATCH] LPC11Uxx USB: fix OUT endpoint stall and endpoint count

A finished OUT transfer left the endpoint stalled until the next receive started. Back-to-back OUT packets then failed on the host. Leave the endpoint inactive so it NAKs.

USB_MAX_ENDPOINTS was 5, which counts EP0. The LPC11Uxx has four endpoints besides EP0. A fifth one wrote past epn_buffer and the endpoint list.
---
 os/hal/ports/LPC/LLD/USB/hal_usb_lld.c | 4 ----
 os/hal/ports/LPC/LLD/USB/hal_usb_lld.h | 2 +-
 2 files changed, 1 insertion(+), 5 deletions(-)

diff --git a/os/hal/ports/LPC/LLD/USB/hal_usb_lld.c b/os/hal/ports/LPC/LLD/USB/hal_usb_lld.c
index aeb38a4736..18177dad04 100644
--- a/os/hal/ports/LPC/LLD/USB/hal_usb_lld.c
+++ b/os/hal/ports/LPC/LLD/USB/hal_usb_lld.c
@@ -161,10 +161,6 @@ static size_t usb_packet_receive(USBDriver *usbp, usbep_t ep) {
     // ReSetup for recieve
     USB_EPLIST->entry[4 * ep] |= EPLIST_ENTRY_NBYTES(epcp->out_maxsize) |
       EPLIST_ADDR(usbp->epn_buffer[ep * 2]) | EPLIST_ENTRY_ACTIVE;
-  } else {
-    if (ep != 0) {
-      USB_EPLIST->entry[4 * ep] |= EPLIST_ENTRY_STALL;
-    }
   }
 
   return n;
diff --git a/os/hal/ports/LPC/LLD/USB/hal_usb_lld.h b/os/hal/ports/LPC/LLD/USB/hal_usb_lld.h
index 4cc3ee7792..978689db83 100644
--- a/os/hal/ports/LPC/LLD/USB/hal_usb_lld.h
+++ b/os/hal/ports/LPC/LLD/USB/hal_usb_lld.h
@@ -34,7 +34,7 @@
 /**
  * @brief   Maximum endpoint address.
  */
-#define USB_MAX_ENDPOINTS                   5
+#define USB_MAX_ENDPOINTS                   4
 
 /**
  * @brief   Status stage handling method.