diff --git a/examples/espressif/esp/src/lwip/exports.zig b/examples/espressif/esp/src/lwip/exports.zig
index 4e4a88e7b..c4daf4beb 100644
--- a/examples/espressif/esp/src/lwip/exports.zig
+++ b/examples/espressif/esp/src/lwip/exports.zig
@@ -24,6 +24,13 @@ export fn lwip_unlock_core_mutex() void {
     core_mutex.unlock();
 }
 
+export fn lwip_assert_core_locked() void {
+    if (c.lock_tcpip_core == null) return;
+
+    const mutex: *rtos.Mutex = @ptrCast(@alignCast(c.lock_tcpip_core));
+    std.debug.assert(mutex.locked != null);
+}
+
 export fn lwip_rand() u32 {
     return esp.rng.random_u32();
 }
diff --git a/examples/espressif/esp/src/lwip/include/arch/cc.h b/examples/espressif/esp/src/lwip/include/arch/cc.h
index df5207f4c..9671a6e97 100644
--- a/examples/espressif/esp/src/lwip/include/arch/cc.h
+++ b/examples/espressif/esp/src/lwip/include/arch/cc.h
@@ -9,9 +9,12 @@ typedef unsigned int sys_prot_t;
 extern uint32_t lwip_rand(void);
 extern void lwip_lock_core_mutex();
 extern void lwip_unlock_core_mutex();
+extern void lwip_assert_core_locked();
 extern void lwip_assert(const char *msg, const char *file, int line);
 extern void lwip_diag(const char *msg, const char *file, int line);
 
+#define LWIP_ASSERT_CORE_LOCKED()   do { lwip_assert_core_locked(); } while (0)
+
 #define LWIP_PLATFORM_DIAG(x)                                                  \
     do {                                                                       \
         lwip_diag((msg), __FILE__, __LINE__);                                  \
diff --git a/modules/lwip/build.zig b/modules/lwip/build.zig
index cfea858e3..54ad40161 100644
--- a/modules/lwip/build.zig
+++ b/modules/lwip/build.zig
@@ -72,6 +72,7 @@ const files = [_][]const u8{
     "core/ipv4/ip4_addr.c",
     "core/ipv4/igmp.c",
     "core/ipv4/icmp.c",
+    "core/ipv4/acd.c",
 
     // IPv6 implementation:
     "core/ipv6/icmp6.c",
diff --git a/modules/lwip/build.zig.zon b/modules/lwip/build.zig.zon
index 692c9058c..5b63c68ce 100644
--- a/modules/lwip/build.zig.zon
+++ b/modules/lwip/build.zig.zon
@@ -7,9 +7,9 @@
     },
     .dependencies = .{
         .lwip = .{
-            //.url = "https://download.savannah.nongnu.org/releases/lwip/lwip-2.1.3.zip",
-            .url = "https://github.com/Ashet-Technologies/deps/raw/refs/heads/main/lwip-2.1.3.zip",
-            .hash = "N-V-__8AAKCP6ADEah-rtpC4uEsB_-GFFCqsNInUAJY7bH3S",
+            // .url = "https://download.savannah.nongnu.org/releases/lwip/lwip-2.2.1.zip",
+            .url = "https://github.com/lwip-tcpip/lwip/archive/refs/tags/STABLE-2_2_1_RELEASE.zip",
+            .hash = "N-V-__8AAGSTdQCcOKeNITCRoYez502saFXZqz4ucBJ4xTa9",
         },
     },
 }