From 5b0b145f1268b47ec22c22da69caccaabd6f72a0 Mon Sep 17 00:00:00 2001
From: matejcik <ja@matejcik.cz>
Date: Tue, 16 Apr 2024 16:59:04 +0200
Subject: [PATCH] build(core): allow custom vendor header for prodtest

to facilitate building prodtest with unsigned VH and then replacing it
---
 build-docker.sh          |  2 ++
 core/SConscript.prodtest | 11 ++++++++++-
 2 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/build-docker.sh b/build-docker.sh
index dbe019a49..44ea4ea9f 100755
--- a/build-docker.sh
+++ b/build-docker.sh
@@ -59,6 +59,7 @@ function help_and_die() {
   echo "  --help"
   echo
   echo "Set PRODUCTION=0 to run non-production builds."
+  echo "Set VENDOR_HEADER=vendorheader_prodtest_unsigned.bin to use the specified vendor header for prodtest."
   exit 0
 }
 
@@ -382,6 +383,7 @@ EOF
       -v "$DIR/build/core$DIRSUFFIX":/build:z \
       --env TREZOR_MODEL="$TREZOR_MODEL" \
       --env PRODUCTION="$PRODUCTION" \
+      --env VENDOR_HEADER="$VENDOR_HEADER" \
       --init \
       "$SNAPSHOT_NAME" \
       /nix/var/nix/profiles/default/bin/nix-shell --run "bash /local/build/$SCRIPT_NAME"
diff --git a/core/SConscript.prodtest b/core/SConscript.prodtest
index 78d4320b9..e1b7c2f79 100644
--- a/core/SConscript.prodtest
+++ b/core/SConscript.prodtest
@@ -195,7 +195,16 @@ obj_program.extend(env.Object(source=SOURCE_HAL))
 
 MODEL_IDENTIFIER = tools.get_model_identifier(TREZOR_MODEL)
 
-if PRODUCTION:
+
+if (vh := ARGUMENTS.get("VENDOR_HEADER", None)) is not None:
+    VENDORHEADER = vh
+elif (vh := os.environ.get("VENDOR_HEADER", None)) is not None:
+    # TODO looking at envvars in a build script is not very nice. But justifiable in case
+    # of vendor header which does not affect reproducibility of the build. Nonetheless,
+    # we should figure out a cleaner way to pass in this argument, without having to teach
+    # the Makefile about it.
+    VENDORHEADER = f'embed/vendorheader/{MODEL_IDENTIFIER}/{vh}'
+elif PRODUCTION:
     VENDORHEADER = f'embed/vendorheader/{MODEL_IDENTIFIER}/vendorheader_prodtest_signed_prod.bin'
 elif BOOTLOADER_DEVEL:
     VENDORHEADER = f'embed/vendorheader/{MODEL_IDENTIFIER}/vendorheader_dev_DO_NOT_SIGN_signed_dev.bin'