diff --git a/src/Makefile b/src/Makefile
index a9fb7b81..38f607cb 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -624,8 +624,10 @@ net:
 	$(eval nnuenet := $(shell grep EvalFile ucioption.cpp | grep Option | sed 's/.*\(nn-[a-z0-9]\{12\}.nnue\).*/\1/'))
 	@echo "Default net: $(nnuenet)"
 	$(eval nnuedownloadurl := https://tests.stockfishchess.org/api/nn/$(nnuenet))
-	$(eval curl_or_wget := $(shell if hash curl 2>/dev/null; then echo "curl -sL"; elif hash wget 2>/dev/null; then echo "wget -qO-"; fi))
+	$(eval curl_or_wget := $(shell if hash curl 2>/dev/null; then echo "curl -skL"; elif hash wget 2>/dev/null; then echo "wget -qO-"; fi))
 	@if test -f "$(nnuenet)"; then echo "Already available."; else echo "Downloading $(nnuedownloadurl)"; $(curl_or_wget) $(nnuedownloadurl) > $(nnuenet); fi
+	$(eval shasum_command := $(shell if hash shasum 2>/dev/null; then echo "shasum -a 256 "; elif hash sha256sum 2>/dev/null; then echo "sha256sum "; fi))
+	@if [ "$(nnuenet)" != "nn-"`$(shasum_command) $(nnuenet) | cut -c1-12`".nnue" ]; then echo "Failed download or $(nnuenet) corrupted, please delete!"; exit 1; fi
 
 # clean binaries and objects
 objclean:
diff --git a/src/ucioption.cpp b/src/ucioption.cpp
index 0a35d01b..2b66a475 100644
--- a/src/ucioption.cpp
+++ b/src/ucioption.cpp
@@ -79,6 +79,8 @@ void init(OptionsMap& o) {
   o["Syzygy50MoveRule"]      << Option(true);
   o["SyzygyProbeLimit"]      << Option(7, 0, 7);
   o["Use NNUE"]              << Option(false, on_use_NNUE);
+  // The default must follow the format nn-[SHA256 first 12 digits].nnue
+  // for the build process (profile-build and fishtest) to work.
   o["EvalFile"]              << Option("nn-82215d0fd0df.nnue", on_eval_file);
 }