diff --git a/system/lib/compiler-rt/readme.txt b/system/lib/compiler-rt/README.md
similarity index 100%
rename from system/lib/compiler-rt/readme.txt
rename to system/lib/compiler-rt/README.md
diff --git a/system/lib/libc/compat/readme.txt b/system/lib/libc/compat/README.md
similarity index 51%
rename from system/lib/libc/compat/readme.txt
rename to system/lib/libc/compat/README.md
index c96c613641c52..8e3170ea0dbaf 100644
--- a/system/lib/libc/compat/readme.txt
+++ b/system/lib/libc/compat/README.md
@@ -1,2 +1,3 @@
-Files in this directory are not strictly standard musl libc, but implemented here for compatibility for Emscripten purposes.
+Files in this directory are not strictly standard musl libc, but implemented
+here for compatibility for Emscripten purposes.
 
diff --git a/system/lib/libcxx/readme.txt b/system/lib/libcxx/README.md
similarity index 100%
rename from system/lib/libcxx/readme.txt
rename to system/lib/libcxx/README.md
diff --git a/system/lib/libcxxabi/readme.txt b/system/lib/libcxxabi/README.md
similarity index 100%
rename from system/lib/libcxxabi/readme.txt
rename to system/lib/libcxxabi/README.md
diff --git a/system/lib/libunwind/readme.txt b/system/lib/libunwind/README.md
similarity index 100%
rename from system/lib/libunwind/readme.txt
rename to system/lib/libunwind/README.md
diff --git a/system/lib/llvm-libc/readme.txt b/system/lib/llvm-libc/README.md
similarity index 100%
rename from system/lib/llvm-libc/readme.txt
rename to system/lib/llvm-libc/README.md
diff --git a/system/lib/llvm-openmp/readme.txt b/system/lib/llvm-openmp/README.md
similarity index 100%
rename from system/lib/llvm-openmp/readme.txt
rename to system/lib/llvm-openmp/README.md
diff --git a/system/lib/update_common.py b/system/lib/update_common.py
index a71991ad1a1e4..ad57b08fb74db 100644
--- a/system/lib/update_common.py
+++ b/system/lib/update_common.py
@@ -68,11 +68,9 @@ def get_llvm_version(upstream_dir):
 
 
 def update_readme(local_dir, llvm_dir):
-  readme_path = os.path.join(local_dir, 'readme.txt')
+  readme_path = os.path.join(local_dir, 'README.md')
   if not os.path.exists(readme_path):
-    readme_path = os.path.join(local_dir, 'README.txt')
-    if not os.path.exists(readme_path):
-      return
+    return
 
   with open(readme_path, 'r') as f:
     content = f.read()
diff --git a/test/freetype/readme.txt b/test/freetype/README.md
similarity index 100%
rename from test/freetype/readme.txt
rename to test/freetype/README.md
diff --git a/test/third_party/bullet/readme.txt b/test/third_party/bullet/README.md
similarity index 100%
rename from test/third_party/bullet/readme.txt
rename to test/third_party/bullet/README.md
diff --git a/test/third_party/cube2hash/readme.txt b/test/third_party/cube2hash/README.md
similarity index 100%
rename from test/third_party/cube2hash/readme.txt
rename to test/third_party/cube2hash/README.md
diff --git a/test/third_party/freetype/readme.txt b/test/third_party/freetype/README.md
similarity index 100%
rename from test/third_party/freetype/readme.txt
rename to test/third_party/freetype/README.md
diff --git a/test/third_party/libiberty/readme.txt b/test/third_party/libiberty/README.md
similarity index 100%
rename from test/third_party/libiberty/readme.txt
rename to test/third_party/libiberty/README.md
diff --git a/test/third_party/openjpeg/readme.txt b/test/third_party/openjpeg/README.md
similarity index 100%
rename from test/third_party/openjpeg/readme.txt
rename to test/third_party/openjpeg/README.md
diff --git a/test/third_party/poppler/readme.txt b/test/third_party/poppler/README.md
similarity index 100%
rename from test/third_party/poppler/readme.txt
rename to test/third_party/poppler/README.md
diff --git a/test/third_party/zlib/readme.txt b/test/third_party/zlib/README.md
similarity index 100%
rename from test/third_party/zlib/readme.txt
rename to test/third_party/zlib/README.md
diff --git a/third_party/closure-compiler/node-externs/readme.txt b/third_party/closure-compiler/README.md
similarity index 100%
rename from third_party/closure-compiler/node-externs/readme.txt
rename to third_party/closure-compiler/README.md