From f6782850bd522d6778766b61c9e02abcd0e0abc4 Mon Sep 17 00:00:00 2001
From: Vicki Pfau <vi@endrift.com>
Date: Wed, 24 Jun 2020 18:09:07 -0700
Subject: [PATCH] GBA BIOS: Fix reloading video registers after reset (fixes
 #1808)

---
 CHANGES        | 1 +
 src/gba/bios.c | 5 +++++
 2 files changed, 6 insertions(+)

diff --git a/CHANGES b/CHANGES
index 8700b8167..26f2dcf37 100644
--- a/CHANGES
+++ b/CHANGES
@@ -3,6 +3,7 @@ Emulation fixes:
  - GB Memory: Fix OAM DMA from top 8 kB
  - GB MBC: Fix MBC1 RAM enable bit selection
  - GB MBC: Fix MBC2 bit selection
+ - GBA BIOS: Fix reloading video registers after reset (fixes mgba.io/i/1808)
 Other fixes:
  - All: Correct format strings for some numbers on Windows (fixes mgba.io/i/1794)
  - GB Core: Fix extracting SRAM when none is present
diff --git a/src/gba/bios.c b/src/gba/bios.c
index 3045fb46c..0a7982ad5 100644
--- a/src/gba/bios.c
+++ b/src/gba/bios.c
@@ -179,6 +179,11 @@ static void _RegisterRamReset(struct GBA* gba) {
 	}
 	if (registers & 0x9C) {
 		gba->video.renderer->reset(gba->video.renderer);
+		gba->video.renderer->writeVideoRegister(gba->video.renderer, REG_DISPCNT, gba->memory.io[REG_DISPCNT >> 1]);
+		int i;
+		for (i = REG_BG0CNT; i < REG_SOUND1CNT_LO; i += 2) {
+			gba->video.renderer->writeVideoRegister(gba->video.renderer, i, gba->memory.io[i >> 1]);
+		}
 	}
 }