diff --git a/packaging/d4r-check.sh b/packaging/d4r-check.sh
index 578a538..eea1d59 100755
--- a/packaging/d4r-check.sh
+++ b/packaging/d4r-check.sh
@@ -75,10 +75,10 @@ for dir in "$ROCM/lib" /opt/rocm/lib /usr/lib /usr/lib64 /usr/lib/x86_64-linux-g
 done
 [ -n "$found" ] && ok "ROCm HIP runtime ($found/libamdhip64.so.7)" || bad "ROCm HIP runtime 7.x (libamdhip64.so.7); re-extract the d4r zip, which includes it in d4r/rocm"
 [ -e /dev/kfd ] && ok "/dev/kfd (ROCm compute device)" || bad "/dev/kfd: the amdgpu compute interface is not available"
-target=""
+target="" best_simds=0
 for props in /sys/class/kfd/kfd/topology/nodes/*/properties; do
   s=$(sed -n 's/^simd_count //p' "$props" 2>/dev/null); t=$(sed -n 's/^gfx_target_version //p' "$props" 2>/dev/null)
-  [ -n "$s" ] && [ "$s" != 0 ] && [ -n "$t" ] && [ "$t" != 0 ] && { target="$t"; break; }
+  [ -n "$s" ] && [ "$s" -gt "$best_simds" ] && [ -n "$t" ] && [ "$t" != 0 ] && { target="$t"; best_simds="$s"; }
 done
 if [ -n "$target" ]; then
   arch=$(printf 'gfx%d%d%x' $((target / 10000)) $(((target / 100) % 100)) $((target % 100)))
diff --git a/scripts/d4r_config.py b/scripts/d4r_config.py
index 04febeb..a70b554 100755
--- a/scripts/d4r_config.py
+++ b/scripts/d4r_config.py
@@ -42,10 +42,10 @@ def config_path(argv):
 
 def main(argv):
     path = config_path(argv)
-    ini = configparser.ConfigParser(inline_comment_prefixes=(";", "#"), interpolation=None)
+    ini = configparser.ConfigParser(inline_comment_prefixes=(";", "#"), interpolation=None, strict=False)
     ini.optionxform = str  # keep [Env] variable names as written
     if path.exists():
-        ini.read(path)
+        ini.read(path, encoding="utf-8-sig")
 
     def get(section, key):
         value = ini.get(section, key, fallback="").strip()
@@ -193,6 +193,8 @@ def main(argv):
 
     if ini.has_section("Env"):
         for key, value in ini.items("Env"):
+            if not (key.isascii() and key.isidentifier()):
+                fail(f"[Env] key {key!r} must be an ASCII identifier")
             env[key] = value.strip()
 
     final = {key: value for key, value in env.items() if key not in os.environ}
diff --git a/scripts/package_release.sh b/scripts/package_release.sh
index 45829c3..d6c19a6 100755
--- a/scripts/package_release.sh
+++ b/scripts/package_release.sh
@@ -16,7 +16,7 @@
 #   D4R_MAX_GLIBC     highest GLIBC ABI the Linux libraries may require     default 2.41
 #   D4R_GPU_ARCHS    GPU targets to build kernels for          default gfx1100 gfx1101 gfx1102 gfx1103 gfx1200 gfx1201
 #                    (RDNA4 targets also get a <target>-fp8 folder: the kernels for d4r.ini NativeFp8 = on)
-#   D4R_OPTISCALER_LICENSE  OptiScaler's LICENSE (GPL-3.0) text; default: the system's SPDX copy
+#   D4R_OPTISCALER_LICENSE  OptiScaler's LICENSE (GPL-3.0) text; default: system SPDX or common-licenses copy
 #   D4R_VKD3D_SRC    vkd3d-proton source checkout, for its license files     default ~/.cache/d4r-vkd3d-proton
 #   D4R_ZLUDA_SRC    ZLUDA source checkout, for its license files            default: D4R_ZLUDA_DIR's ../d4r-zluda-upstream
 #   SOURCE_DATE_EPOCH  timestamp given to every packaged file                default: the last commit's
@@ -52,6 +52,9 @@ ARCHS="${D4R_GPU_ARCHS:-gfx1100 gfx1101 gfx1102 gfx1103 gfx1200 gfx1201}"
 for f in "$ZLUDA/libnvcuda.so" "$VKD3D/d3d12.dll" "$VKD3D/d3d12core.dll" "$ROCM_RUNTIME/lib/libamdhip64.so.7"; do
   [[ -f "$f" ]] || { echo "missing $f (the ROCm runtime comes from scripts/fetch_rocm_runtime.sh)" >&2; exit 2; }
 done
+OPTISCALER_LICENSE="${D4R_OPTISCALER_LICENSE:-/usr/share/licenses/spdx/GPL-3.0-only.txt}"
+[[ -n "${D4R_OPTISCALER_LICENSE:-}" || -f "$OPTISCALER_LICENSE" ]] || OPTISCALER_LICENSE=/usr/share/common-licenses/GPL-3
+[[ -f "$OPTISCALER_LICENSE" ]] || { echo "missing OptiScaler GPL-3.0 license; set D4R_OPTISCALER_LICENSE to an existing file" >&2; exit 2; }
 
 # D4R_SKIP_BUILD=1 packages the shim and bridge already in build/ (e.g. the binaries that were tested)
 if [[ "${D4R_SKIP_BUILD:-0}" != 1 ]]; then
@@ -205,7 +208,7 @@ cp "$ZLUDA_SRC/LICENSE-MIT" "$L/ZLUDA-LICENSE-MIT.txt"
 cp "$ZLUDA_SRC/ext/llvm-project/llvm/LICENSE.TXT" "$L/LLVM-LICENSE.txt"
 cp "$VKD3D_SRC/LICENSE" "$L/vkd3d-proton-LICENSE.txt"
 cp "$VKD3D_SRC/COPYING" "$L/vkd3d-proton-COPYING.txt"
-cp "${D4R_OPTISCALER_LICENSE:-/usr/share/licenses/spdx/GPL-3.0-only.txt}" "$L/OptiScaler-LICENSE-GPL-3.0.txt"
+cp "$OPTISCALER_LICENSE" "$L/OptiScaler-LICENSE-GPL-3.0.txt"
 for f in "$ROCM_RUNTIME"/licenses/*; do cp "$f" "$L/ROCm-$(basename "$f")"; done
 mkdir -p "$STAGE/d4r/source/patches"
 cp -r "$ROOT/patches/zluda" "$ROOT/patches/vkd3d-proton" "$STAGE/d4r/source/patches/"