From d29d7cebdfcd9780719f22781b341af673c829af Mon Sep 17 00:00:00 2001
From: paulb-nl <boumanpaul@gmail.com>
Date: Mon, 13 Jan 2025 17:12:53 +0100
Subject: [PATCH] N163: default to having PRG RAM if no NES2.0 header

---
 NES.sv               | 3 ++-
 rtl/mappers/Namco.sv | 4 +++-
 2 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/NES.sv b/NES.sv
index 2cbc0bc..c1fdbaa 100644
--- a/NES.sv
+++ b/NES.sv
@@ -1469,7 +1469,8 @@ wire [3:0] prg_nvram = (is_nes20 ? ines[10][7:4] : 4'h0);
 wire       piano = is_nes20 && (ines[15][5:0] == 6'h19);
 wire has_saves = ines[6][1];
 
-assign mapper_flags[63:35] = 'd0;
+assign mapper_flags[63:36] = 'd0;
+assign mapper_flags[35]    = is_nes20;
 assign mapper_flags[34:31] = prg_nvram; //NES 2.0 Save RAM shift size (64 << size)
 assign mapper_flags[30]    = piano;
 assign mapper_flags[29:26] = prgram; //NES 2.0 PRG RAM shift size (64 << size)
diff --git a/rtl/mappers/Namco.sv b/rtl/mappers/Namco.sv
index bbf2724..8377814 100644
--- a/rtl/mappers/Namco.sv
+++ b/rtl/mappers/Namco.sv
@@ -71,7 +71,9 @@ wire [18:10] chr_aoutm;
 
 wire [3:0] prg_ram_size = flags[29:26];
 wire [3:0] prg_nvram_size = flags[34:31];
-wire has_prg_ram = |{prg_ram_size, prg_nvram_size};
+wire is_nes20 = flags[35];
+// Default to having PRG RAM if no NES2.0 header
+wire has_prg_ram = |{~is_nes20, prg_ram_size, prg_nvram_size};
 // 2KB PRG RAM for mapper 210
 wire ram_2k = (prg_ram_size == 4'h5 || prg_nvram_size == 4'h5);