Cult of GBA BIOS incompatibility warning

.gitignore

@@ -43,6 +43,8 @@ __pycache__/
 /gba/*.sav
 /gba/.map
 /gba/compile_commands.json
+/gba/tools/write_bios
+/gba/tools/gba_bios.h
 /nes/obj/nes/*.s
 /nes/obj/nes/*.sav
 /nes/obj/nes/last-commit*

gba/README.md

@@ -117,6 +117,26 @@ or macOS, once you have installed `gba-dev` using pacman, type these:
     source /etc/profile.d/devkit-env.sh
     make
 
+In 2024, unreliability of devkitPro's download servers led the team
+to investigate replacing devkitARM with [Wonderful Toolchain].
+
+Some GBA emulators, such as Mesen, do not ship with a free
+reimplementation of Game Boy Advance BIOS.  GBA owners can
+[dump the authentic BIOS] using a GBA flash cartridge.
+Emulator-only users can use [Cult of GBA's reimplementation], either
+using a GNU binutils distribution (such as devkitARM or Wonderful)
+to build it from source code or using the `tools/get_bios.sh`
+script with a native C compiler to retrieve and unpack the copy of
+Cult of GBA BIOS distributed with [SkyEmu].  **Careful:** As of
+August 2024, Cult of GBA BIOS works only with the devkitARM build,
+not the Wonderful build.  (This has been filed as [issue #14].)
+
+[Wonderful Toolchain]: https://wonderful.asie.pl/
+[dump the authentic BIOS]: https://glazedbelmont.github.io/gbabiosdump/
+[Cult of GBA's reimplementation]: https://github.com/Cult-of-GBA/BIOS
+[SkyEmu]: https://github.com/skylersaleh/SkyEmu
+[issue #14]: https://github.com/Cult-of-GBA/BIOS/issues/14
+
 Contributors
 ------------
 * Concept: Artemio Urbina [@Artemio]

gba/tools/get_bios.sh

@@ -0,0 +1,12 @@
+#!/bin/bash
+# Downloader for SkyEmu distribution of Cult of GBA BIOS
+# Copyright 2024 Damian Yerrick
+# SPDX-License-Identifier: FSFAP
+#
+# Script to download and produce the file gba_bios.bin based on
+# Cult of GBA BIOS <https://github.com/Cult-of-GBA/BIOS>
+# which is under Expat license
+set -e
+curl --remote-name --referer 'https://github.com/SourMesen/Mesen2/' 'https://raw.githubusercontent.com/skylersaleh/SkyEmu/555bd384f3346b7cd3103d74d5191c3b86312157/src/gba_bios.h'
+gcc -std=c11 -s -Os -o write_bios write_bios.c
+./write_bios

gba/tools/write_bios.c

@@ -0,0 +1,12 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <assert.h>
+#include "gba_bios.h"
+static_assert(sizeof(gba_bios_bin) == 16384);
+int main(void) {
+  FILE *outfp = fopen("gba_bios.bin", "wb");
+  if (!outfp) return EXIT_FAILURE;
+  size_t written = fwrite(gba_bios_bin, sizeof gba_bios_bin, 1, outfp);
+  fclose(outfp);
+  return !written;
+}

nes/src/helppages.txt

@@ -143,11 +143,11 @@ color levels.
 A: Toggle bars' brightness
 Select: Play 1 kHz tone
 
-Use blue filters or some TVs'
-blue-only mode to confirm
-color balance. Because of
-shortcuts in the NES PPU's
-composite output stage,
+Use blue filters or some
+TVs' blue-only mode to
+confirm color balance.
+Because of shortcuts in the
+NES PPU's composite output,
 these colors are impure.
 On NTSC, green and magenta
 have correct hues, and