From d291059937464db13c702d1c03c8662a7deaa56a Mon Sep 17 00:00:00 2001
From: BrokeStudio <contact@brokestudio.fr>
Date: Mon, 18 Dec 2023 11:04:20 +0100
Subject: [PATCH] rainbow: fixed PRG RAM 4K mode issue

---
 Core/NES/Mappers/Homebrew/Rainbow.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Core/NES/Mappers/Homebrew/Rainbow.h b/Core/NES/Mappers/Homebrew/Rainbow.h
index a0130ffe1..0d5e65df4 100644
--- a/Core/NES/Mappers/Homebrew/Rainbow.h
+++ b/Core/NES/Mappers/Homebrew/Rainbow.h
@@ -1225,7 +1225,7 @@ class Rainbow : public BaseMapper
 					break;
 				case PRG_RAM_MODE_1:
 					// 2 x 4K
-					prgIdx = ((addr >> 12) & 0x07) - 6;
+					prgIdx = ((addr >> 12) & 0x07) - 5;
 					if(((_prg[prgIdx] & 0x8000) >> 14) != 0)
 						return WritePrgRam(addr, value); // FPGA_RAM or WRAM