From 0dcd233cbbcd86930962cd999cd2ca52f136c30d Mon Sep 17 00:00:00 2001
From: Lior Halphon <LIJI32@gmail.com>
Date: Sat, 23 Oct 2021 23:51:48 +0300
Subject: [PATCH] Writes to SVBK should work before the boot ROM is disabled

---
 Core/memory.c | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/Core/memory.c b/Core/memory.c
index 1720356a..2fdc72de 100644
--- a/Core/memory.c
+++ b/Core/memory.c
@@ -1234,12 +1234,11 @@ static void write_high_memory(GB_gameboy_t *gb, uint16_t addr, uint8_t value)
                 gb->io_registers[GB_IO_DMA] = value;
                 return;
             case GB_IO_SVBK:
-                if (!gb->cgb_mode) {
-                    return;
-                }
-                gb->cgb_ram_bank = value & 0x7;
-                if (!gb->cgb_ram_bank) {
-                    gb->cgb_ram_bank++;
+                if (gb->cgb_mode || (GB_is_cgb(gb) && !gb->boot_rom_finished)) {
+                    gb->cgb_ram_bank = value & 0x7;
+                    if (!gb->cgb_ram_bank) {
+                        gb->cgb_ram_bank++;
+                    }
                 }
                 return;
             case GB_IO_VBK: