From 79c8551c0599ea087502ae59bbe72d1ae8bbabf1 Mon Sep 17 00:00:00 2001
From: gbc dev <gbc@localhost>
Date: Sat, 18 Jul 2026 22:45:06 +0200
Subject: tools: mk_sl0pboy_bios.py - fork the CGB boot ROM's GAME BOY ->
 SL0PBOY

The stock CGB boot ROM draws its GAME BOY wordmark from a 192-byte blob
at $0607 (routine $03F0 copies it to VRAM tiles $08-$37: 48 tiles, 4
bytes each, every byte a row doubled vertically). This re-encodes that
blob with a bold-italic SL0PBOY bitmap of the same size and patches it
in place over a local bios/gbc_bios.bin -> bios/sl0pboy_bios.bin. No
code moves; the cart's own Nintendo logo ($104) is untouched so the
integrity check still passes and the boot hands off normally.

bios/ stays gitignored (copyrighted boot ROM); run this to produce the
fork locally. Verified end to end: logo drop + color + chime -> gbos.
---
 .gitignore | 3 +++
 1 file changed, 3 insertions(+)

(limited to '.gitignore')

diff --git a/.gitignore b/.gitignore
index 5965ca5..dbd0fc4 100644
--- a/.gitignore
+++ b/.gitignore
@@ -6,3 +6,6 @@
 roms/
 compile_commands.json
 /bios/
+
+# generated boot-ROM logo preview
+bios/*.preview.png
-- 
cgit v1.3.1-sl0p