From c5d434e7d0ff3b4aaa2154f4bc6bf3b7e31e1689 Mon Sep 17 00:00:00 2001
From: Abdessamad Derraz <3028866+Abdess@users.noreply.github.com>
Date: Fri, 16 Oct 2026 09:49:32 +0200
Subject: [PATCH] fix: tag the clk western sms bios for brazil

---
 emulators/clk.yml            |  6 +++---
 tests/test_profile_checks.py | 16 ++++++++++++++++
 2 files changed, 19 insertions(+), 3 deletions(-)

diff --git a/emulators/clk.yml b/emulators/clk.yml
index 475a0a62..f9afdcbb 100644
--- a/emulators/clk.yml
+++ b/emulators/clk.yml
@@ -708,12 +708,12 @@ files:
     path: MasterSystem/bios.sms
     system: sega-mastersystem
     description: "European/US Master System BIOS"
-    region: [north-america, europe]
+    region: [north-america, europe, brazil]
     size: 8192
     crc32: "0072ed54"
     required: false
-    note: "Optional. Boots cartridge directly if absent."
-    source_ref: "Machines/Utility/ROMCatalogue.cpp:764-771"
+    note: "Optional. Boots cartridge directly if absent. Loaded for every region but Japan."
+    source_ref: "Machines/Utility/ROMCatalogue.cpp:764-771, Machines/MasterSystem/MasterSystem.cpp:137-140, Analyser/Static/Sega/Target.hpp:24-29"
 
   - name: japanese-bios.sms
     path: MasterSystem/japanese-bios.sms
diff --git a/tests/test_profile_checks.py b/tests/test_profile_checks.py
index 8624b9ed..e3897b2f 100644
--- a/tests/test_profile_checks.py
+++ b/tests/test_profile_checks.py
@@ -344,5 +344,21 @@ class AzaharConsoleUniqueData(_Probe):
                 self.assertFalse(self.accepts("azahar", name, b"\0" * (size + 7)))
 
 
+class ClkMasterSystemBios(unittest.TestCase):
+    """CLK loads the western Master System BIOS for every region but Japan,
+    Brazil included (Machines/MasterSystem/MasterSystem.cpp:137-140,
+    Analyser/Static/Sega/Target.hpp:24-29 at 53a1ee7). Tagged north-america
+    and europe only, a Brazilian pack dropped it for the Japanese one."""
+
+    def test_brazil_keeps_the_western_bios(self):
+        import region
+
+        index = region.build_region_index({"clk": _profile("clk")})
+        group = {"sms": [("MasterSystem/bios.sms", "bios.sms"),
+                         ("MasterSystem/japanese-bios.sms", "japanese-bios.sms")]}
+        drops = region.resolve_region_drops(group, index, ["brazil"])
+        self.assertEqual(drops, {"MasterSystem/japanese-bios.sms"})
+
+
 if __name__ == "__main__":
     unittest.main()