diff --git a/app/lua/lbaselib.c b/app/lua/lbaselib.c
index 160e9640..8b8eceb5 100644
--- a/app/lua/lbaselib.c
+++ b/app/lua/lbaselib.c
@@ -24,7 +24,7 @@
 ** model but changing `fputs' to put the strings at a proper place
 ** (a console window or a log file, for instance).
 */
-#ifdef LUA_CROSS_COMPILER
+#if defined(LUA_USE_ESP8266)
 #undef puts
 #define puts(s) printf("%s",s)
 #endif
diff --git a/app/lua/ldebug.c b/app/lua/ldebug.c
index ca05727e..57bd376b 100644
--- a/app/lua/ldebug.c
+++ b/app/lua/ldebug.c
@@ -248,6 +248,7 @@ static int stripdebug (lua_State *L, Proto *f, int level) {
         f->packedlineinfo = luaM_freearray(L, f->packedlineinfo, sizepackedlineinfo, unsigned char);
         len += sizepackedlineinfo;
       }
+      // fall-through
     case 1:
       f->locvars = luaM_freearray(L, f->locvars, f->sizelocvars, struct LocVar);
       f->upvalues = luaM_freearray(L, f->upvalues, f->sizeupvalues, TString *);
@@ -501,7 +502,7 @@ static Instruction symbexec (const Proto *pt, int lastpc, int reg) {
       case OP_FORLOOP:
       case OP_FORPREP:
         checkreg(pt, a+3);
-        /* go through */
+        /* fall-through */
       case OP_JMP: {
         int dest = pc+1+b;
         /* not full check and jump is forward and do not skip `lastpc'? */
diff --git a/app/lua/lflash.c b/app/lua/lflash.c
index 6875106d..59c5b964 100644
--- a/app/lua/lflash.c
+++ b/app/lua/lflash.c
@@ -29,7 +29,7 @@
  * process.
  */
 
-static char    *flashAddr;
+static const char *flashAddr;
 static uint32_t flashSize;
 static uint32_t flashAddrPhys;
 static uint32_t flashSector;
@@ -106,20 +106,20 @@ LUA_API void dumpStrings(lua_State *L) {
  * writes are suppressed if the global writeToFlash is false.  This is used in
  * phase I where the pass is used to size the structures in flash.
  */
-static char *flashPosition(void){
+static const char *flashPosition(void){
   return  flashAddr + curOffset;
 }
 
 
-static char *flashSetPosition(uint32_t offset){
+static const char *flashSetPosition(uint32_t offset){
   NODE_DBG("flashSetPosition(%04x)\n", offset);
   curOffset = offset;
   return flashPosition();
 }
 
 
-static char *flashBlock(const void* b, size_t size)  {
-  void *cur = flashPosition();
+static const char *flashBlock(const void* b, size_t size)  {
+  const void *cur = flashPosition();
   NODE_DBG("flashBlock((%04x),%p,%04x)\n", curOffset,b,size);
   lua_assert(ALIGN_BITS(b) == 0 && ALIGN_BITS(size) == 0);
   platform_flash_write(b, flashAddrPhys+curOffset, size);
@@ -137,6 +137,10 @@ static void flashErase(uint32_t start, uint32_t end){
     platform_flash_erase_sector( flashSector + i );
 }
 
+static int loadLFS (lua_State *L);
+static int loadLFSgc (lua_State *L);
+static void procFirstPass (void);
+
 /* =====================================================================================
  * luaN_init() is exported via lflash.h.
  * The first is the startup hook used in lstate.c and the last two are
@@ -171,7 +175,7 @@ LUAI_FUNC void luaN_init (lua_State *L) {
   }
 
   if ((fh->flash_sig & (~FLASH_SIG_ABSOLUTE)) != FLASH_SIG ) {
-    NODE_ERR("Flash sig not correct: 0x%08x vs 0x%08x\n",
+    NODE_ERR("LFS sig not correct: 0x%x vs expected 0x%x\n",
        fh->flash_sig & (~FLASH_SIG_ABSOLUTE), FLASH_SIG);
     return;
   }
@@ -208,6 +212,7 @@ LUALIB_API void luaL_lfsreload (lua_State *L) {
     return;
   }
 
+
  /*
   * Do a protected call of loadLFS.
   *
@@ -346,13 +351,13 @@ static void put_byte (uint8_t value) {
 }
 
 
-static uint8_t recall_byte (unsigned offset) {
+static uint8_t recall_byte (uint32_t offset) {
   if(offset > DICTIONARY_WINDOW || offset >= out->ndx)
     flash_error("invalid dictionary offset on inflate");
   /* ndx starts at 1. Need relative to 0 */
-  unsigned n   = out->ndx - offset;
-  unsigned pos = n % WRITE_BLOCKSIZE;
-  unsigned blockNo = out->ndx / WRITE_BLOCKSIZE - n  / WRITE_BLOCKSIZE;
+  uint32_t n   = out->ndx - offset;
+  uint32_t pos = n % WRITE_BLOCKSIZE;
+  uint32_t blockNo = out->ndx / WRITE_BLOCKSIZE - n  / WRITE_BLOCKSIZE;
   return out->block[blockNo]->byte[pos];
 }
 
@@ -386,7 +391,7 @@ void procFirstPass (void) {
          fh->flash_size > flashSize ||
          out->flagsLen != 1 + (out->flashLen/WORDSIZE - 1) / BITS_PER_WORD)
       flash_error("LFS length mismatch");
-    out->flags = luaM_newvector(out->L, out->flagsLen, unsigned);
+    out->flags = luaM_newvector(out->L, out->flagsLen, uint32_t);
   }
 
   /* update running CRC */
@@ -412,7 +417,7 @@ void procSecondPass (void) {
                   (out->flashLen % WRITE_BLOCKSIZE) / WORDSIZE :
                   WRITE_BLOCKSIZE / WORDSIZE;
   uint32_t *buf = (uint32_t *) out->buffer.byte;
-  uint32_t  flags = 0;
+  uint32_t flags = 0;
  /*
   * Relocate all the addresses tagged in out->flags.  This can't be done in
   * place because the out->blocks are still in use as dictionary content so
@@ -423,7 +428,7 @@ void procSecondPass (void) {
     if ((i&31)==0)
       flags = out->flags[out->flagsNdx++];
     if (flags&1)
-      buf[i] = WORDSIZE*buf[i] + cast(uint32_t, flashAddr);
+      buf[i] = WORDSIZE*buf[i] + cast(uint32_t, flashAddr); // mapped, not phys
   }
  /*
   * On first block, set the flash_sig has the in progress bit set and this
@@ -468,7 +473,7 @@ static int loadLFS (lua_State *L) {
   in->len = vfs_size(in->fd);
   if (in->len <= 200 ||        /* size of an empty luac output */
       vfs_lseek(in->fd, in->len-4, VFS_SEEK_SET) != in->len-4 ||
-      vfs_read(in->fd, &out->len, sizeof(unsigned)) != sizeof(unsigned))
+      vfs_read(in->fd, &out->len, sizeof(uint32_t)) != sizeof(uint32_t))
     flash_error("read error on LFS image file");
   vfs_lseek(in->fd, 0, VFS_SEEK_SET);
 
diff --git a/app/lua/llex.c b/app/lua/llex.c
index 965f5a24..3c978c94 100644
--- a/app/lua/llex.c
+++ b/app/lua/llex.c
@@ -61,6 +61,7 @@ static void save (LexState *ls, int c) {
 
 
 void luaX_init (lua_State *L) {
+  (void)L;
 }
 
 
diff --git a/app/lua/lmathlib.c b/app/lua/lmathlib.c
index cb9586fc..c03d34ec 100644
--- a/app/lua/lmathlib.c
+++ b/app/lua/lmathlib.c
@@ -359,5 +359,6 @@ LROT_END(math, NULL, 0)
 ** Open math library
 */
 LUALIB_API int luaopen_math (lua_State *L) {
+  (void)L;
   return 0;
 }
diff --git a/app/lua/lnodemcu.c b/app/lua/lnodemcu.c
index 0b791bb8..d3d96408 100644
--- a/app/lua/lnodemcu.c
+++ b/app/lua/lnodemcu.c
@@ -118,6 +118,7 @@ LUALIB_API int luaL_posttask( lua_State* L, int prio ) {          // [-1, +0, -]
 }
 #else
 LUALIB_API int luaL_posttask( lua_State* L, int prio ) { 
+  (void)L; (void)prio;
   return 0;
 } /* Dummy stub on host */
 #endif
diff --git a/app/lua/lnodemcu.h b/app/lua/lnodemcu.h
index e5fedec6..b6363944 100644
--- a/app/lua/lnodemcu.h
+++ b/app/lua/lnodemcu.h
@@ -45,9 +45,11 @@
   static ROTable_entry LOCK_IN_SECTION(s) rt ## _entries[] = {
 #define LROT_END(rt,mt,f)    {NULL, LRO_NILVAL} }; \
   const ROTable rt ## _ROTable = { \
-    (GCObject *)1, LUA_TROTABLE, LROT_MARKED, \
-    cast(lu_byte, ~(f)), (sizeof(rt ## _entries)/sizeof(ROTable_entry)) - 1, \
-    cast(Table *, mt), cast(ROTable_entry *, rt ## _entries) };
+    .next = (GCObject *)1, .tt = LUA_TROTABLE, .marked = LROT_MARKED, \
+    .flags = cast(lu_byte, ~(f)), \
+    .lsizenode = (sizeof(rt ## _entries)/sizeof(ROTable_entry)) - 1, \
+    .metatable = cast(Table *, mt), \
+    .entry = cast(ROTable_entry *, rt ## _entries) };
 #define LROT_BREAK(rt)       };
 
 #define LROT_MASK(m)         cast(lu_byte, 1<<TM_ ## m)
@@ -65,10 +67,9 @@
 #define LROT_MASK_NEWINDEX   LROT_MASK(NEWINDEX)
 #define LROT_MASK_GC_INDEX   (LROT_MASK_GC | LROT_MASK_INDEX)
 
-/* Maximum length of a rotable name and of a string key*/
+#define LUA_MAX_ROTABLE_NAME 32  /* Maximum length of a rotable name and of a string key*/
 
 #ifdef LUA_CORE
 
 #endif
 #endif
-
diff --git a/app/lua/loadlib.c b/app/lua/loadlib.c
index cb17e42e..20bed4c8 100644
--- a/app/lua/loadlib.c
+++ b/app/lua/loadlib.c
@@ -619,6 +619,7 @@ static int ll_seeall (lua_State *L) {
 
 static void setpath (lua_State *L, const char *fieldname, const char *envname,
                                    const char *def) {
+  (void)envname;
   const char *path = NULL;  /* getenv(envname) not used in NodeMCU */;
   if (path == NULL)  /* no environment variable? */
     lua_pushstring(L, def);  /* use default */
diff --git a/app/lua/lobject.c b/app/lua/lobject.c
index d9bedc6a..39512b8c 100644
--- a/app/lua/lobject.c
+++ b/app/lua/lobject.c
@@ -68,10 +68,7 @@ int luaO_log2 (unsigned int x) {
   while (x >= 256) { l += 8; x >>= 8; }
   return l + log_2[x];
 #else
- /* Use Normalization Shift Amount Unsigned:  0x1=>31 up to 0xffffffff =>0
-  * See Xtensa Instruction Set Architecture (ISA) Refman  P 462 */
-  asm volatile ("nsau %0, %1;" :"=r"(x) : "r"(x));
-  return 31 - x;
+  return 31 - __builtin_clz(x);
 #endif
 }
 
diff --git a/app/lua/lobject.h b/app/lua/lobject.h
index 74680d49..0e8e8478 100644
--- a/app/lua/lobject.h
+++ b/app/lua/lobject.h
@@ -28,7 +28,7 @@
 #define LUA_TUPVAL	(LAST_TAG+2)
 #define LUA_TDEADKEY	(LAST_TAG+3)
 
-#ifdef LUA_USE_ESP
+#ifdef LUA_USE_ESP8266
 /*
 ** force aligned access to critical fields in Flash-based structures
 ** wo is the offset of aligned word in bytes 0,4,8,..
diff --git a/app/lua/ltable.c b/app/lua/ltable.c
index a9940dce..9bfd0abc 100644
--- a/app/lua/ltable.c
+++ b/app/lua/ltable.c
@@ -336,6 +336,7 @@ static Node *find_prev_node(Node *mp, Node *next) {
 ** (colliding node is in its main position), moving node goes to an empty position.
 */
 static int move_node (lua_State *L, Table *t, Node *node) {
+  (void)L;
   Node *mp = mainposition(t, key2tval(node));
   /* if node is in it's main position, don't need to move node. */
   if (mp == node) return 1;
@@ -374,6 +375,7 @@ static int move_node (lua_State *L, Table *t, Node *node) {
 
 
 static int move_number (lua_State *L, Table *t, Node *node) {
+  (void)L;
   int key;
   lua_Number n = nvalue(key2tval(node));
   lua_number2int(key, n);
diff --git a/app/lua/ltablib.c b/app/lua/ltablib.c
index 000d9a6c..57e66e24 100644
--- a/app/lua/ltablib.c
+++ b/app/lua/ltablib.c
@@ -277,5 +277,6 @@ LROT_BEGIN(tab_funcs, NULL, 0)
 LROT_END(tab_funcs, NULL, 0)
 
 LUALIB_API int luaopen_table (lua_State *L) {
+  (void)L;
   return 1;
 }
diff --git a/app/lua53/lauxlib.h b/app/lua53/lauxlib.h
index 50269ee5..2ef11b30 100644
--- a/app/lua53/lauxlib.h
+++ b/app/lua53/lauxlib.h
@@ -144,6 +144,9 @@ LUALIB_API void (luaL_requiref) (lua_State *L, const char *modname,
 #define luaL_loadbuffer(L,s,sz,n)	luaL_loadbufferx(L,s,sz,n,NULL)
 
 
+#define luaL_checkfunction(L,n)        luaL_checktype(L, (n), LUA_TFUNCTION);
+#define luaL_checktable(L,n)   luaL_checktype(L, (n), LUA_TTABLE);
+
 /*
 ** {======================================================
 ** Generic Buffer manipulation
@@ -227,7 +230,8 @@ LUALIB_API void (luaL_openlib) (lua_State *L, const char *libname,
 
 /* print a string */
 #if !defined(lua_writestring)
-#ifdef LUA_USE_ESP8266
+#ifdef LUA_USE_ESP
+void output_redirect(const char *str, size_t l);
 #define lua_writestring(s,l)  output_redirect((s),(l))
 #else
 #define lua_writestring(s,l)   fwrite((s), sizeof(char), (l), stdout)
@@ -290,11 +294,8 @@ LUALIB_API int  (luaL_pushlfsdts) (lua_State *L);
 LUALIB_API void (luaL_lfsreload) (lua_State *L);
 LUALIB_API int  (luaL_posttask) (lua_State* L, int prio);
 LUALIB_API int  (luaL_pcallx) (lua_State *L, int narg, int nres);
-
 #define luaL_pushlfsmodule(l) lua_pushlfsfunc(L)
 
 /* }============================================================ */
 
 #endif
-
-
diff --git a/app/lua53/ldblib.c b/app/lua53/ldblib.c
index 0a36a530..5be2ece2 100644
--- a/app/lua53/ldblib.c
+++ b/app/lua53/ldblib.c
@@ -464,6 +464,7 @@ LROT_BEGIN(dblib, NULL, 0)
 LROT_END(dblib, NULL, 0)
 
 LUAMOD_API int luaopen_debug (lua_State *L) {
+  (void)L;
   return 0;
 }
 
diff --git a/app/lua53/ldump.c b/app/lua53/ldump.c
index 90bbdfaa..3dfee3c6 100644
--- a/app/lua53/ldump.c
+++ b/app/lua53/ldump.c
@@ -272,6 +272,7 @@ static int stripdebug (lua_State *L, Proto *f, int level) {
         f->lineinfo = luaM_freearray(L, f->lineinfo, f->sizelineinfo);
         len += f->sizelineinfo;
       }
+      // fall-through
     case 1:
       for (i=0; i<f->sizeupvalues; i++)
         f->upvalues[i].name = NULL;
diff --git a/app/lua53/lmathlib.c b/app/lua53/lmathlib.c
index 46ee1b3b..352249cb 100644
--- a/app/lua53/lmathlib.c
+++ b/app/lua53/lmathlib.c
@@ -394,6 +394,7 @@ LROT_END(mathlib, NULL, 0)
 ** Open math library
 */
 LUAMOD_API int luaopen_math (lua_State *L) {
+  (void)L;
   return 0;
 }
 
diff --git a/app/lua53/lnodemcu.c b/app/lua53/lnodemcu.c
index e124eb1d..2b1d6e9b 100644
--- a/app/lua53/lnodemcu.c
+++ b/app/lua53/lnodemcu.c
@@ -296,7 +296,7 @@ LUA_API void lua_getlfsconfig (lua_State *L, int *config) {
   }
 }
 
-LUA_API int  (lua_pushlfsindex) (lua_State *L) {
+LUA_API int lua_pushlfsindex(lua_State *L) {
   lua_lock(L);
   setobj2n(L, L->top, &G(L)->LFStable);
   api_incr_top(L);
@@ -309,7 +309,7 @@ LUA_API int  (lua_pushlfsindex) (lua_State *L) {
  * one upvalue that must be the set to the _ENV variable when its closure is
  * created, and as such this parallels some ldo.c processing.
  */
-LUA_API int  (lua_pushlfsfunc) (lua_State *L) {
+LUA_API int lua_pushlfsfunc(lua_State *L) {
   lua_lock(L);
   const TValue *t = &G(L)->LFStable;
   if (ttisstring(L->top-1) && ttistable(t)) {
@@ -341,7 +341,7 @@ LUA_API int  (lua_pushlfsfunc) (lua_State *L) {
 /*
  * Return an array of functions in LFS
  */
-LUALIB_API int  (luaL_pushlfsmodules) (lua_State *L) {
+LUALIB_API int luaL_pushlfsmodules(lua_State *L) {
   int i = 1;
   if (lua_pushlfsindex(L) == LUA_TNIL)
     return 0;                                 /* return nil if LFS not loaded */
@@ -357,7 +357,7 @@ LUALIB_API int  (luaL_pushlfsmodules) (lua_State *L) {
   return 1;
 }
 
-LUALIB_API int  (luaL_pushlfsdts) (lua_State *L) {
+LUALIB_API int luaL_pushlfsdts(lua_State *L) {
   int config[5];
   lua_getlfsconfig(L, config);
   lua_pushinteger(L, config[4]);
@@ -427,7 +427,9 @@ static const char *readF (lua_State *L, void *ud, size_t *size) {
 
 static void eraseLFS(LFSflashState *F) {
   lu_int32 i;
+#ifdef LUA_USE_ESP
   printf("\nErasing LFS from flash addr 0x%06x", F->addrPhys);
+#endif
   unlockFlashWrite();
   for (i = 0; i < F->size; i += FLASH_PAGE_SIZE) {
     size_t *f = cast(size_t *, F->addr + i/sizeof(*f));
@@ -436,11 +438,13 @@ static void eraseLFS(LFSflashState *F) {
 #ifdef LUA_USE_ESP
     if (*f == ~0 && !memcmp(f, f + 1, FLASH_PAGE_SIZE - sizeof(*f)))
       continue;
+    printf(".");
 #endif
     platform_flash_erase_sector(s);
-    printf(".");
   }
+#ifdef LUA_USE_ESP
   printf(" to 0x%06x\n", F->addrPhys + F->size-1);
+#endif
   flush_icache(F);
   lockFlashWrite();
 }
@@ -623,7 +627,6 @@ LUALIB_API void luaL_lfsreload (lua_State *L) {
 
 
 #ifdef LUA_USE_ESP
-extern void lua_main(void);
 /*
 ** Task callback handler. Uses luaN_call to do a protected call with full traceback
 */
@@ -634,7 +637,7 @@ static void do_task (platform_task_param_t task_fn_ref, uint8_t prio) {
     return;
   }
   if (prio < LUA_TASK_LOW|| prio > LUA_TASK_HIGH)
-    luaL_error(L, "invalid posk task");
+    luaL_error(L, "invalid post task");
 /* Pop the CB func from the Reg */
   lua_rawgeti(L, LUA_REGISTRYINDEX, (int) task_fn_ref);
   luaL_checktype(L, -1, LUA_TFUNCTION);
@@ -662,7 +665,7 @@ LUALIB_API int luaL_posttask ( lua_State* L, int prio ) {         // [-1, +0, -]
     }
     return task_fn_ref;
   } else {
-    return luaL_error(L, "invalid posk task");
+    return luaL_error(L, "invalid post task");
   }
 }
 #else
@@ -670,6 +673,7 @@ LUALIB_API int luaL_posttask ( lua_State* L, int prio ) {         // [-1, +0, -]
 ** Task execution isn't supported on HOST builds so returns a -1 status
 */
 LUALIB_API int luaL_posttask( lua_State* L, int prio ) {            // [-1, +0, -]
+  (void)L; (void)prio;
   return -1;
 }
 #endif
diff --git a/app/lua53/loadlib.c b/app/lua53/loadlib.c
index 74e69a4f..6c049dcf 100644
--- a/app/lua53/loadlib.c
+++ b/app/lua53/loadlib.c
@@ -421,7 +421,7 @@ static int ll_loadlib (lua_State *L) {
 ** =======================================================
 */
 
-#ifdef LUA_USE_ESP8266
+#ifdef LUA_USE_ESP
 #define file_t int
 #undef fopen
 #undef fclose
diff --git a/app/lua53/lobject.c b/app/lua53/lobject.c
index 384c765c..867720f7 100644
--- a/app/lua53/lobject.c
+++ b/app/lua53/lobject.c
@@ -63,13 +63,7 @@ int luaO_fb2int (int x) {
 ** Computes ceil(log2(x))
 */
 int luaO_ceillog2 (unsigned int x) {
-#ifdef LUA_USE_ESP
- /* Use Normalization Shift Amount Unsigned:  0x1=>31 up to 0xffffffff =>0
-  * See Xtensa Instruction Set Architecture (ISA) Refman  P 462 */
-  x--;
-  asm volatile ("nsau %0, %1;" :"=r"(x) : "r"(x));
-  return 32 - x;
-#else
+#ifdef LUA_CROSS_COMPILER
   static const lu_byte log_2[256] = {  /* log_2[i] = ceil(log2(i - 1)) */
     0,1,2,2,3,3,3,3,4,4,4,4,4,4,4,4,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,
     6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,
@@ -84,6 +78,8 @@ int luaO_ceillog2 (unsigned int x) {
   x--;
   while (x >= 256) { l += 8; x >>= 8; }
   return l + log_2[x];
+#else
+  return (x == 1) ? 0 : 32 - __builtin_clz(x - 1);
 #endif
 }
 
diff --git a/app/lua53/lobject.h b/app/lua53/lobject.h
index 5441f81a..7e01944c 100644
--- a/app/lua53/lobject.h
+++ b/app/lua53/lobject.h
@@ -80,7 +80,7 @@
 ** wo is the offset of aligned word in bytes 0,4,8,..
 ** bo is the field within the word in bits 0..31
 */
-#ifdef LUA_USE_ESP
+#if defined(LUA_USE_ESP8266)
 #define GET_BYTE_FN(name,t,wo,bo) \
 static inline lu_int32 get ## name(const void *o) { \
   lu_int32 res;  /* extract named field */ \
diff --git a/app/lua53/lstate.c b/app/lua53/lstate.c
index a2d68eaf..b524b188 100644
--- a/app/lua53/lstate.c
+++ b/app/lua53/lstate.c
@@ -42,12 +42,15 @@
 ** created; the seed is used to randomize hashes.
 */
 #if !defined(luai_makeseed)
-#if defined(LUA_USE_ESP)
+#if defined(LUA_USE_ESP8266)
 static inline unsigned int luai_makeseed(void) {
   unsigned int r;
   asm volatile("rsr %0, ccount" : "=r"(r));
   return r;
 }
+#elif defined(LUA_USE_ESP)
+# include "esp_random.h"
+# define luai_makeseed()    esp_random()
 #else
 #include <time.h>
 #define luai_makeseed()		cast(unsigned int, time(NULL))
diff --git a/app/lua53/ltablib.c b/app/lua53/ltablib.c
index 48d58bbf..77715598 100644
--- a/app/lua53/ltablib.c
+++ b/app/lua53/ltablib.c
@@ -438,6 +438,7 @@ LROT_BEGIN(tab_funcs, NULL, 0)
 LROT_END(tab_funcs, NULL, 0)
 
 LUAMOD_API int luaopen_table (lua_State *L) {
+  (void)L;
   return 0;
 }
 
diff --git a/app/lua53/lua.h b/app/lua53/lua.h
index 58eb5a40..4ca58385 100644
--- a/app/lua53/lua.h
+++ b/app/lua53/lua.h
@@ -465,6 +465,8 @@ struct lua_Debug {
   struct CallInfo *i_ci;  /* active function */
 };
 
+int lua_main(void);
+
 /* }====================================================================== */
 
 /* NodeMCU extensions to the standard API */
diff --git a/app/lua53/lutf8lib.c b/app/lua53/lutf8lib.c
index a139bed9..4fff0f2d 100644
--- a/app/lua53/lutf8lib.c
+++ b/app/lua53/lutf8lib.c
@@ -258,6 +258,7 @@ LROT_END(utf8, LROT_TABLEREF(utf8_meta), 0)
 
 
 LUAMOD_API int luaopen_utf8 (lua_State *L) {
+  (void)L;
   return 0;
 }