diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index a5abd22..68953d8 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -463,6 +463,27 @@ jobs:
           path: status
           retention-days: 1
 
+  # test that compilation is warning free under clang
+  clang:
+    runs-on: ubuntu-20.04
+    steps:
+      - uses: actions/checkout@v2
+      - name: install
+        run: |
+          # need toml, also pip3 isn't installed by default?
+          sudo apt-get update -qq
+          sudo apt-get install -qq python3 python3-pip
+          sudo pip3 install toml
+      - name: install-clang
+        run: |
+          sudo apt-get update -qq
+          sudo apt-get install -qq clang
+          echo "CC=clang" >> $GITHUB_ENV
+          clang --version
+      # no reason to not test again
+      - name: test-clang
+        run: make test TESTFLAGS+="-k"
+
   # self-host with littlefs-fuse for a fuzz-like test
   fuse:
     runs-on: ubuntu-22.04
diff --git a/Makefile b/Makefile
index 501cb6e..f810a0b 100644
--- a/Makefile
+++ b/Makefile
@@ -77,8 +77,7 @@ override CFLAGS += -DLFS_YES_TRACE
 endif
 override CFLAGS += -g3
 override CFLAGS += -I.
-override CFLAGS += -std=c99 -Wall -pedantic
-override CFLAGS += -Wextra -Wshadow -Wjump-misses-init -Wundef
+override CFLAGS += -std=c99 -Wall -Wextra -pedantic
 override CFLAGS += -ftrack-macro-expansion=0
 ifdef YES_COV
 override CFLAGS += --coverage
diff --git a/README.md b/README.md
index 584ada3..32b3793 100644
--- a/README.md
+++ b/README.md
@@ -252,7 +252,7 @@ License Identifiers that are here available: http://spdx.org/licenses/
 [mklfs]: https://github.com/whitecatboard/Lua-RTOS-ESP32/tree/master/components/mklfs/src
 [Lua RTOS]: https://github.com/whitecatboard/Lua-RTOS-ESP32
 [Mbed OS]: https://github.com/armmbed/mbed-os
-[LittleFileSystem]: https://os.mbed.com/docs/mbed-os/v5.12/apis/littlefilesystem.html
+[LittleFileSystem]: https://os.mbed.com/docs/mbed-os/latest/apis/littlefilesystem.html
 [SPIFFS]: https://github.com/pellepl/spiffs
 [Dhara]: https://github.com/dlbeer/dhara
 [littlefs-python]: https://pypi.org/project/littlefs-python/
diff --git a/bd/lfs_filebd.c b/bd/lfs_filebd.c
index e214822..780c8f9 100644
--- a/bd/lfs_filebd.c
+++ b/bd/lfs_filebd.c
@@ -147,7 +147,7 @@ int lfs_filebd_sync(const struct lfs_config *cfg) {
     // file sync
     lfs_filebd_t *bd = cfg->context;
     #ifdef _WIN32
-    int err = FlushFileBuffers((HANDLE) _get_osfhandle(fd)) ? 0 : -1;
+    int err = FlushFileBuffers((HANDLE) _get_osfhandle(bd->fd)) ? 0 : -1;
     #else
     int err = fsync(bd->fd);
     #endif
diff --git a/lfs.c b/lfs.c
index af46039..48a10e8 100644
--- a/lfs.c
+++ b/lfs.c
@@ -865,11 +865,6 @@ static int lfs_dir_traverse(lfs_t *lfs,
                 };
                 sp += 1;
 
-                dir = dir;
-                off = off;
-                ptag = ptag;
-                attrs = attrs;
-                attrcount = attrcount;
                 tmask = 0;
                 ttag = 0;
                 begin = 0;
@@ -1162,6 +1157,7 @@ static lfs_stag_t lfs_dir_fetchmatch(lfs_t *lfs,
                         dir->erased = false;
                         break;
                     }
+                    return err;
                 }
                 lfs_pair_fromle32(temptail);
             }
@@ -3007,12 +3003,14 @@ cleanup:
     return err;
 }
 
+#ifndef LFS_NO_MALLOC
 static int lfs_file_rawopen(lfs_t *lfs, lfs_file_t *file,
         const char *path, int flags) {
     static const struct lfs_file_config defaults = {0};
     int err = lfs_file_rawopencfg(lfs, file, path, flags, &defaults);
     return err;
 }
+#endif
 
 static int lfs_file_rawclose(lfs_t *lfs, lfs_file_t *file) {
 #ifndef LFS_READONLY
@@ -4204,7 +4202,7 @@ static int lfs_rawmount(lfs_t *lfs, const struct lfs_config *cfg) {
 
             if (superblock.block_size != lfs->cfg->block_size) {
                 LFS_ERROR("Invalid block size (%"PRIu32" != %"PRIu32")",
-                        superblock.block_count, lfs->cfg->block_count);
+                        superblock.block_size, lfs->cfg->block_size);
                 err = LFS_ERR_INVAL;
                 goto cleanup;
             }
diff --git a/lfs.h b/lfs.h
index 9bdfaa0..ab53452 100644
--- a/lfs.h
+++ b/lfs.h
@@ -532,8 +532,8 @@ int lfs_file_open(lfs_t *lfs, lfs_file_t *file,
 // are values from the enum lfs_open_flags that are bitwise-ored together.
 //
 // The config struct provides additional config options per file as described
-// above. The config struct must be allocated while the file is open, and the
-// config struct must be zeroed for defaults and backwards compatibility.
+// above. The config struct must remain allocated while the file is open, and
+// the config struct must be zeroed for defaults and backwards compatibility.
 //
 // Returns a negative error code on failure.
 int lfs_file_opencfg(lfs_t *lfs, lfs_file_t *file,
diff --git a/lfs_util.h b/lfs_util.h
index 3971882..7f79def 100644
--- a/lfs_util.h
+++ b/lfs_util.h
@@ -168,10 +168,9 @@ static inline int lfs_scmp(uint32_t a, uint32_t b) {
 
 // Convert between 32-bit little-endian and native order
 static inline uint32_t lfs_fromle32(uint32_t a) {
-#if !defined(LFS_NO_INTRINSICS) && ( \
-    (defined(  BYTE_ORDER  ) && defined(  ORDER_LITTLE_ENDIAN  ) &&   BYTE_ORDER   ==   ORDER_LITTLE_ENDIAN  ) || \
+#if (defined(  BYTE_ORDER  ) && defined(  ORDER_LITTLE_ENDIAN  ) &&   BYTE_ORDER   ==   ORDER_LITTLE_ENDIAN  ) || \
     (defined(__BYTE_ORDER  ) && defined(__ORDER_LITTLE_ENDIAN  ) && __BYTE_ORDER   == __ORDER_LITTLE_ENDIAN  ) || \
-    (defined(__BYTE_ORDER__) && defined(__ORDER_LITTLE_ENDIAN__) && __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__))
+    (defined(__BYTE_ORDER__) && defined(__ORDER_LITTLE_ENDIAN__) && __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__)
     return a;
 #elif !defined(LFS_NO_INTRINSICS) && ( \
     (defined(  BYTE_ORDER  ) && defined(  ORDER_BIG_ENDIAN  ) &&   BYTE_ORDER   ==   ORDER_BIG_ENDIAN  ) || \
@@ -197,10 +196,9 @@ static inline uint32_t lfs_frombe32(uint32_t a) {
     (defined(__BYTE_ORDER  ) && defined(__ORDER_LITTLE_ENDIAN  ) && __BYTE_ORDER   == __ORDER_LITTLE_ENDIAN  ) || \
     (defined(__BYTE_ORDER__) && defined(__ORDER_LITTLE_ENDIAN__) && __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__))
     return __builtin_bswap32(a);
-#elif !defined(LFS_NO_INTRINSICS) && ( \
-    (defined(  BYTE_ORDER  ) && defined(  ORDER_BIG_ENDIAN  ) &&   BYTE_ORDER   ==   ORDER_BIG_ENDIAN  ) || \
+#elif (defined(  BYTE_ORDER  ) && defined(  ORDER_BIG_ENDIAN  ) &&   BYTE_ORDER   ==   ORDER_BIG_ENDIAN  ) || \
     (defined(__BYTE_ORDER  ) && defined(__ORDER_BIG_ENDIAN  ) && __BYTE_ORDER   == __ORDER_BIG_ENDIAN  ) || \
-    (defined(__BYTE_ORDER__) && defined(__ORDER_BIG_ENDIAN__) && __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__))
+    (defined(__BYTE_ORDER__) && defined(__ORDER_BIG_ENDIAN__) && __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__)
     return a;
 #else
     return (((uint8_t*)&a)[0] << 24) |