Warn when SGB compatibility is set without old licensee 0x33

Rangi42 · Nov 1, 2023 · a6fb6cd · a6fb6cd
1 parent 32bc68d
commit a6fb6cd
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Showing 4 changed files with 7 additions and 0 deletions.
diff --git a/src/fix/main.c b/src/fix/main.c
@@ -967,6 +967,10 @@ static void processFile(int input, int output, char const *name, off_t fileSize)
 
 	if (oldLicensee != UNSPECIFIED)
 		overwriteByte(rom0, 0x14B, oldLicensee, "old licensee code");
+	else if (sgb && rom0[0x14B] != 0x33)
+		fprintf(stderr,
+			"warning: SGB compatibility enabled, but old licensee was %#x, not 0x33\n",
+			rom0[0x14B]);
 
 	if (romVersion != UNSPECIFIED)
 		overwriteByte(rom0, 0x14C, romVersion, "mask ROM version number");

diff --git a/test/fix/sgb-old-licensee.bin b/test/fix/sgb-old-licensee.bin
diff --git a/test/fix/sgb-old-licensee.err b/test/fix/sgb-old-licensee.err
@@ -0,0 +1,2 @@
+warning: Overwrote a non-zero byte in the SGB flag
+warning: SGB compatibility enabled, but old licensee was 0xc5, not 0x33
diff --git a/test/fix/sgb-old-licensee.flags b/test/fix/sgb-old-licensee.flags
@@ -0,0 +1 @@
+-s