diff --git a/CMakeLists.txt b/CMakeLists.txt
index 26316b2..895552d 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -128,7 +128,7 @@ function(componentize OUTPUT)
     add_custom_command(
             OUTPUT ${OUTPUT}.wasm
             WORKING_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}
-            COMMAND ${CMAKE_COMMAND} -E env "PATH=${WASM_TOOLS_DIR};${WIZER_DIR};$ENV{PATH}" ${RUNTIME_DIR}/componentize.sh ${SOURCES} -o ${OUTPUT}.wasm
+            COMMAND ${CMAKE_COMMAND} ${RUNTIME_DIR}/componentize.sh ${SOURCES} -o ${OUTPUT}.wasm
             DEPENDS ${ARG_SOURCES} ${RUNTIME_DIR}/componentize.sh starling.wasm
             VERBATIM
     )
diff --git a/builtins/web/fetch/headers.cpp b/builtins/web/fetch/headers.cpp
index 085a99c..6751740 100644
--- a/builtins/web/fetch/headers.cpp
+++ b/builtins/web/fetch/headers.cpp
@@ -101,7 +101,15 @@ host_api::HostString normalize_and_validate_header_value(JSContext *cx, HandleVa
   }
   bool valid = normalize_header_value(value);
   if (!valid) {
-    api::throw_error(cx, FetchErrors::InvalidHeaderValue, fun_name, value.begin());
+    // need to coerce to utf8 to report the error value
+    JS::RootedString str(cx, JS::ToString(cx, value_val));
+    if (!str) {
+      return host_api::HostString{};
+    }
+    auto maybe_utf8 = core::encode(cx, str);
+    if (maybe_utf8) {
+      api::throw_error(cx, FetchErrors::InvalidHeaderValue, fun_name, maybe_utf8.begin());
+    }
     return host_api::HostString{};
   }
   return value;
diff --git a/componentize.sh b/componentize.sh
index e57f328..729a5cb 100755
--- a/componentize.sh
+++ b/componentize.sh
@@ -2,8 +2,8 @@
 
 #set -euo pipefail
 
-wizer="${WIZER:-wizer}"
-wasm_tools="${WASM_TOOLS:-wasm-tools}"
+wizer="${WIZER:-@WIZER_DIR@/wizer}"
+wasm_tools="${WASM_TOOLS:-@WASM_TOOLS_BIN@}"
 weval="${WEVAL:-@WEVAL_BIN@}"
 aot=@AOT@
 preopen_dir="${PREOPEN_DIR:-}"