For extracting GOG Konami Collector's Series

gog_extract_konami_collectors_series.sh

#!/bin/bash

# Extractor for game ROMs from Konami Collector's Series.
#
# Usage: gog_extract_konami_collectors_series.sh <path_to>/cc.exe
#
# Make sure you have xxd hexdump tool and dd installed.
#

# ROM locations
#
# Note: ROM files didn't change between different GOG builds, but their location has.
# 
# For galaxy build GOG v4 - 2025-07-15T17:22:10+0000 (Gen 2) (Build id: 58807482570125138)
# Everything shifted by 5120 bytes less compared to the old builds
#
# Castlevania    : 01d170 - 03d16f (0x20000 bytes), starts as: 00010203040506070004a000be0007f01ea5ff29181d0780
# Castlevania II : 03d170 - 07d16f (0x40000 bytes), starts as: e931d8701d00e445b0e34037e475e3207087e492e34291e4
# Castlevania III: 07d170 - 0dd16f (0x60000 bytes), starts as: 80ac4e05b90f80854618690185476000040206a5320aa8b9
# Contra         : 0dd170 - 0fd16f (0x20000 bytes), starts as: 00078068800081a9809d9805a9229d8805a9059d5803a540
# Jackal         : 0fd180 - 11d17f (0x20000 bytes), starts as: 0001020304050607ad2901c934d009c6eed012a90985ee60
# Super C        : 11d180 - 15d17f (0x40000 bytes), starts as: 30a90085728562a900a4cad0020901a4cbd0020902a88884

#
# For galaxy builds GOG v3 - 2021-02-03T06:48:56+0000 (Gen 2) (Build id: 54100975267659913) and older:
#
# Castlevania    : 01e570 - 03e56f (0x20000 bytes) starts as: 00010203040506070004a000be0007f01ea5ff29181d0780
# Castlevania II : 03e570 - 07e56f (0x40000 bytes) starts as: e931d8701d00e445b0e34037e475e3207087e492e34291e4
# Castlevania III: 07e570 - 0de56f (0x60000 bytes) starts as: 80ac4e05b90f80854618690185476000040206a5320aa8b9
# Contra         : 0de570 - 0fe56f (0x20000 bytes) starts as: 00078068800081a9809d9805a9229d8805a9059d5803a540
# Jackal         : 0fe580 - 11e57f (0x20000 bytes) starts as: 0001020304050607ad2901c934d009c6eed012a90985ee60
# Super C        : 11e580 - 15e57f (0x40000 bytes) starts as: 30a90085728562a900a4cad0020901a4cbd0020902a88884

# Expected md5sum of the produced functional ROMs:
#
# 1e1e452a83b23701119c70770cea10c9  castlevania.nes
# 4dda679420cc4067510501b238222330  castlevania_ii.nes
# 6284615b9e2125445e909c89df0dd71e  castlevania_iii.nes
# 2686c4b168a7e82bdb2c6fb3061fcbfd  contra.nes
# 8e29ebef55fcf1197e110b9247c9ec5d  jackal.nes
# c951d1d48dc9811562cf46bcad26ca66  super_c.nes

header_hex1='4e45531a080021000000000000000000'
header_hex2='4e45531a081010000000000000000000'
header_hex3='4e45531a101050000000000000000000'
header_hex4='4e45531a081041000000000000000000'

source="$1"
if ! [ -e "$source" ]; then
   echo "Error: can't find ${source}!"
   exit 1
fi

declare -A roms

# old builds
#roms["castlevania"]="0x1e570:0x20000"
#roms["castlevania_ii"]="0x3e570:0x40000"
#roms["castlevania_iii"]="0x7e570:0x60000"
#roms["contra"]="0xde570:0x20000"
#roms["jackal"]="0xfe580:0x20000"
#roms["super_c"]="0x11e580:0x40000"

# new builds
roms["castlevania"]="0x1d170:0x20000"
roms["castlevania_ii"]="0x3d170:0x40000"
roms["castlevania_iii"]="0x7d170:0x60000"
roms["contra"]="0xdd170:0x20000"
roms["jackal"]="0xfd180:0x20000"
roms["super_c"]="0x11d180:0x40000"

declare -A headers

headers["castlevania"]=$header_hex1
headers["castlevania_ii"]=$header_hex2
headers["castlevania_iii"]=$header_hex3
headers["contra"]=$header_hex1
headers["jackal"]=$header_hex1
headers["super_c"]=$header_hex4

for rom in "${!roms[@]}"; do
  offset=${roms[$rom]%%:*}
  length=${roms[$rom]##*:}

  target="${rom}.nes"
  echo "Composing ${target}"

  dd if="$source" of="${rom}.tmp" skip=$(($offset))B count=$(($length))B bs=10M
  cat <(echo ${headers[$rom]} | xxd --revert --plain) "${rom}.tmp" > "$target"
  rm -v "${rom}.tmp"
done

Speeding up dd usage with large block size and byte offest / count (that seems to be a poorly documented dd feature).

GOG uploaded a new build of with different cc.exe. note that you have to use an older build for now.

Updated the script to new build