diff --git a/basisu_tool.cpp b/basisu_tool.cpp
index 941c98f..7f0ae6e 100644
--- a/basisu_tool.cpp
+++ b/basisu_tool.cpp
@@ -7754,7 +7754,8 @@ static bool run_codec_test_case(basisu::job_pool& jp, const std::string& dir, co
 
 static uint32_t codec_test_num_threads()
 {
-	uint32_t n = std::thread::hardware_concurrency();
+	//uint32_t n = std::thread::hardware_concurrency();
+	uint32_t n = get_num_hardware_threads();
 	return n ? n : 1;
 }
 
diff --git a/bin/basisu_mt.wasm b/bin/basisu_mt.wasm
index 77c2529..4997ace 100644
Binary files a/bin/basisu_mt.wasm and b/bin/basisu_mt.wasm differ
diff --git a/bin/basisu_st.wasm b/bin/basisu_st.wasm
index 0d9f158..9c2c417 100644
Binary files a/bin/basisu_st.wasm and b/bin/basisu_st.wasm differ