diff --git a/repos/libports/ports/lwip.hash b/repos/libports/ports/lwip.hash
index 981382168..7280f2720 100644
--- a/repos/libports/ports/lwip.hash
+++ b/repos/libports/ports/lwip.hash
@@ -1 +1 @@
-3608c569747383625a1bca182683c3668fa630b5
+136ee70f33ffced072262d589c24ab3252d15eff
diff --git a/repos/libports/ports/lwip.port b/repos/libports/ports/lwip.port
index 873924eaa..29dacc0f7 100644
--- a/repos/libports/ports/lwip.port
+++ b/repos/libports/ports/lwip.port
@@ -14,7 +14,8 @@ PATCHES := $(addprefix src/lib/lwip/,window_scaling.patch \
                                      errno.patch \
                                      libc_select_notify.patch \
                                      sockets_c_errno.patch \
-                                     sol_socket_definition.patch)
+                                     sol_socket_definition.patch \
+                                     api_msg.patch)
 
 PATCH_OPT := -p1 -d src/lib/lwip
 
diff --git a/repos/libports/src/lib/lwip/api_msg.patch b/repos/libports/src/lib/lwip/api_msg.patch
new file mode 100644
index 000000000..a8888dbee
--- /dev/null
+++ b/repos/libports/src/lib/lwip/api_msg.patch
@@ -0,0 +1,13 @@
+The write offset was not always reset after a write finished resulting in the
+failed assertion "already writing or closing".
+
+--- a/src/api/api_msg.c
++++ b/src/api/api_msg.c
+@@ -1340,6 +1340,7 @@ err_mem:
+        and back to application task */
+     conn->current_msg->err = err;
+     conn->current_msg = NULL;
++    conn->write_offset = 0;
+     conn->state = NETCONN_NONE;
+ #if LWIP_TCPIP_CORE_LOCKING
+     if ((conn->flags & NETCONN_FLAG_WRITE_DELAYED) != 0)