diff --git a/scripts/build_windows.sh b/scripts/build_windows.sh
index c9d4bd860..efbefda0e 100755
--- a/scripts/build_windows.sh
+++ b/scripts/build_windows.sh
@@ -2,6 +2,12 @@
 
 echo "- - - - - - - - - - Windows Setup Script - - - - - - - - - -"
 
+# Mirrors the steps in .github/workflows/windows-build.yml so a local MSYS2
+# build matches CI. Builds go through the nimble build system: Nim/Nimble are
+# installed via scripts/install_nim.sh + install_nimble.sh, dependencies are
+# fetched into nimbledeps/ by `nimble setup --localdeps`, and the nat-libs and
+# bearssl C sources are rebuilt from there.
+
 success_count=0
 failure_count=0
 
@@ -18,39 +24,38 @@ execute_command() {
 }
 
 echo "1. -.-.-.-- Set PATH -.-.-.-"
-export PATH="/c/msys64/usr/bin:/c/msys64/mingw64/bin:/c/msys64/usr/lib:/c/msys64/mingw64/lib:$PATH"
+export PATH="$HOME/.nimble/bin:/c/msys64/usr/bin:/c/msys64/mingw64/bin:/c/msys64/usr/lib:/c/msys64/mingw64/lib:$PATH"
 
 echo "2. -.-.-.- Verify dependencies -.-.-.-"
-execute_command "which gcc g++ make cmake cargo upx rustc python"
+execute_command "which gcc g++ make cmake cargo upx rustc python nasm"
 
 echo "3. -.-.-.- Updating submodules -.-.-.-"
 execute_command "git submodule update --init --recursive"
 
-echo "4. -.-.-.- Creating tmp directory -.-.-.-"
+echo "4. -.-.-.- Installing nasm -.-.-.-"
+execute_command "bash scripts/install_nasm_in_windows.sh"
+
+echo "5. -.-.-.- Installing Nim and Nimble -.-.-.-"
+execute_command "make install-nimble"
+
+echo "6. -.-.-.- Patch nimble.lock for Windows nim checksum -.-.-.-"
+# nimble.exe uses Windows Git (core.autocrlf=true by default), which converts
+# LF->CRLF on checkout. This changes the SHA1 of the nim package source tree
+# relative to the Linux-computed checksum stored in nimble.lock. Patch the lock
+# file with the Windows-computed checksum before nimble reads it.
+execute_command "sed -i 's/68bb85cbfb1832ce4db43943911b046c3af3caab/a092a045d3a427d127a5334a6e59c76faff54686/g' nimble.lock"
+
+echo "7. -.-.-.- Installing nimble deps -.-.-.-"
+execute_command "nimble setup --localdeps -y"
+execute_command "make rebuild-nat-libs-nimbledeps CC=gcc"
+execute_command "make rebuild-bearssl-nimbledeps CC=gcc"
+execute_command "touch nimbledeps/.nimble-setup"
+
+echo "8. -.-.-.- Creating tmp directory -.-.-.-"
 execute_command "mkdir -p tmp"
 
-echo "5. -.-.-.- Building Nim -.-.-.-"
-cd vendor/nimbus-build-system/vendor/Nim
-execute_command "./build_all.bat"
-cd ../../../..
-
-echo "6. -.-.-.- Building libunwind -.-.-.-"
-cd vendor/nim-libbacktrace
-execute_command "make all V=1 -j8"
-cd ../../
-
-echo "7. -.-.-.- Building miniupnpc -.-.-.- "
-cd vendor/nim-nat-traversal/vendor/miniupnp/miniupnpc
-execute_command "make -f Makefile.mingw CC=gcc CXX=g++ libminiupnpc.a V=1 -j8"
-cd ../../../../..
-
-echo "8. -.-.-.- Building libnatpmp -.-.-.- "
-cd ./vendor/nim-nat-traversal/vendor/libnatpmp-upstream
-make CC="gcc -fPIC -D_WIN32_WINNT=0x0600 -DNATPMP_STATICLIB" libnatpmp.a V=1 -j8
-cd ../../../../
-
 echo "9. -.-.-.- Building wakunode2 -.-.-.- "
-execute_command "make wakunode2 LOG_LEVEL=DEBUG V=1 -j8"
+execute_command "make wakunode2 LOG_LEVEL=DEBUG V=3 -j8"
 
 echo "10. -.-.-.- Building libwaku -.-.-.- "
 execute_command "make libwaku STATIC=0 LOG_LEVEL=DEBUG V=1 -j8"
diff --git a/scripts/install_nim.sh b/scripts/install_nim.sh
index 42aa88ecd..b75826378 100755
--- a/scripts/install_nim.sh
+++ b/scripts/install_nim.sh
@@ -5,8 +5,9 @@
 # Installs to ~/.nim/nim-<version>/ and symlinks binaries into ~/.nimble/bin/,
 # which is the idiomatic Nim location already on PATH.
 #
-# Pre-built binaries are downloaded from nim-lang.org when available.
-# Falls back to building from source otherwise (e.g. macOS on older releases).
+# Pre-built binaries are downloaded from nim-lang.org: a .zip on Windows
+# (nim-<version>_x64.zip), a .tar.xz on Linux/macOS. On Unix, falls back to
+# building from source when no pre-built tarball exists.
 
 set -e
 
@@ -44,16 +45,64 @@ if [ -n "${nim_ver}" ]; then
   echo "INFO: Nim ${nim_ver} found in PATH; installing Nim ${NIM_VERSION} to ${NIM_DEST}." >&2
 fi
 
+<<<<<<< HEAD
+=======
 OS=$(uname -s | tr 'A-Z' 'a-z' | sed 's/darwin/macosx/')
 ARCH=$(uname -m | sed 's/x86_64/x64/;s/aarch64/arm64/')
 
 BINARY_URL="https://nim-lang.org/download/nim-${NIM_VERSION}-${OS}_${ARCH}.tar.xz"
+>>>>>>> master
 WORK_DIR=$(mktemp -d)
 trap 'rm -rf "${WORK_DIR}"' EXIT
 
-echo "Checking for pre-built Nim ${NIM_VERSION} (${OS}_${ARCH})..."
-HTTP_STATUS=$(curl -sI "${BINARY_URL}" | head -1 | grep -oE '[0-9]{3}' || true)
+case "$(uname -s)" in
+MINGW* | MSYS* | CYGWIN*)
+  # Windows: Nim ships as a zip named nim-<version>_<arch>.zip
+  # (no OS segment, .zip rather than .tar.xz, and no source-build fallback).
+  case "$(uname -m)" in
+  x86_64 | amd64) WIN_ARCH=x64 ;;
+  *) WIN_ARCH=x32 ;;
+  esac
+  BINARY_URL="https://nim-lang.org/download/nim-${NIM_VERSION}_${WIN_ARCH}.zip"
 
+<<<<<<< HEAD
+  echo "Downloading pre-built Nim ${NIM_VERSION} (windows_${WIN_ARCH}) from ${BINARY_URL}..."
+  curl -fL "${BINARY_URL}" -o "${WORK_DIR}/nim.zip"
+  unzip -q "${WORK_DIR}/nim.zip" -d "${WORK_DIR}"
+  SRC_DIR="${WORK_DIR}/nim-${NIM_VERSION}"
+  ;;
+*)
+  OS=$(uname -s | tr 'A-Z' 'a-z' | sed 's/darwin/macosx/')
+  ARCH=$(uname -m | sed 's/x86_64/x64/;s/aarch64/arm64/')
+
+  BINARY_URL="https://nim-lang.org/download/nim-${NIM_VERSION}-${OS}_${ARCH}.tar.xz"
+
+  echo "Checking for pre-built Nim ${NIM_VERSION} (${OS}_${ARCH})..."
+  HTTP_STATUS=$(curl -sI "${BINARY_URL}" | head -1 | grep -oE '[0-9]{3}' || true)
+
+  if [ "${HTTP_STATUS}" = "200" ]; then
+    echo "Downloading pre-built binary from ${BINARY_URL}..."
+    curl -fL "${BINARY_URL}" -o "${WORK_DIR}/nim.tar.xz"
+    tar -xJf "${WORK_DIR}/nim.tar.xz" -C "${WORK_DIR}"
+    SRC_DIR="${WORK_DIR}/nim-${NIM_VERSION}"
+  else
+    echo "No pre-built binary found for ${OS}_${ARCH}. Building from source..."
+    SRC_URL="https://github.com/nim-lang/Nim/archive/refs/tags/v${NIM_VERSION}.tar.gz"
+    curl -fL "${SRC_URL}" -o "${WORK_DIR}/nim-src.tar.gz"
+    tar -xzf "${WORK_DIR}/nim-src.tar.gz" -C "${WORK_DIR}"
+    cd "${WORK_DIR}/Nim-${NIM_VERSION}"
+    sh build_all.sh
+    SRC_DIR="${WORK_DIR}/Nim-${NIM_VERSION}"
+  fi
+  ;;
+esac
+
+# rm -rf can fail with "Directory not empty" on overlay filesystems (e.g. Docker).
+# Using cp -r src/. dst/ handles both cases: dst absent (clean) or partially present.
+rm -rf "${NIM_DEST}" 2>/dev/null || true
+mkdir -p "${NIM_DEST}"
+cp -r "${SRC_DIR}/." "${NIM_DEST}/"
+=======
 if [ "${HTTP_STATUS}" = "200" ]; then
   echo "Downloading pre-built binary from ${BINARY_URL}..."
   curl -fL "${BINARY_URL}" -o "${WORK_DIR}/nim.tar.xz"
@@ -68,6 +117,7 @@ else
   sh build_all.sh
   SRC_DIR="${WORK_DIR}/Nim-${NIM_VERSION}"
 fi
+>>>>>>> master
 
 # rm -rf can fail with "Directory not empty" on overlay filesystems (e.g. Docker).
 # Using cp -r src/. dst/ handles both cases: dst absent (clean) or partially present.
diff --git a/scripts/install_nimble.sh b/scripts/install_nimble.sh
index dba2d6612..871f6d784 100755
--- a/scripts/install_nimble.sh
+++ b/scripts/install_nimble.sh
@@ -19,7 +19,17 @@ if [ -z "${NIMBLE_VERSION}" ]; then
   exit 1
 fi
 
+<<<<<<< HEAD
+# On Windows (MSYS2) the binaries carry a .exe extension.
+EXE=""
+case "$(uname -s)" in
+MINGW* | MSYS* | CYGWIN*) EXE=".exe" ;;
+esac
+
+NIMBLE_BIN="${HOME}/.nimble/bin/nimble${EXE}"
+=======
 NIMBLE_BIN="${HOME}/.nimble/bin/nimble"
+>>>>>>> master
 
 # 1. Already installed at the right version?
 if [ -x "${NIMBLE_BIN}" ]; then
@@ -32,7 +42,11 @@ if [ -x "${NIMBLE_BIN}" ]; then
 fi
 
 # 2. Already compiled into pkgs2/ from a previous (possibly partial) run?
+<<<<<<< HEAD
+PKGS2_NIMBLE=$(ls -dt "${HOME}/.nimble/pkgs2/nimble-${NIMBLE_VERSION}-"*/nimble${EXE} \
+=======
 PKGS2_NIMBLE=$(ls -dt "${HOME}/.nimble/pkgs2/nimble-${NIMBLE_VERSION}-"*/nimble \
+>>>>>>> master
   2>/dev/null | head -1 || true)
 if [ -n "${PKGS2_NIMBLE}" ] && [ -x "${PKGS2_NIMBLE}" ]; then
   echo "Nimble ${NIMBLE_VERSION} found in pkgs2, re-linking to ${NIMBLE_BIN}."
@@ -42,7 +56,11 @@ if [ -n "${PKGS2_NIMBLE}" ] && [ -x "${PKGS2_NIMBLE}" ]; then
 fi
 
 # 3. Build from source.
+<<<<<<< HEAD
+NIM_BIN="${HOME}/.nimble/bin/nim${EXE}"
+=======
 NIM_BIN="${HOME}/.nimble/bin/nim"
+>>>>>>> master
 if [ ! -x "${NIM_BIN}" ]; then
   NIM_BIN="$(command -v nim)"
 fi
@@ -60,11 +78,19 @@ echo "Building nimble ${NIMBLE_VERSION} with $("${NIM_BIN}" --version | head -1)
 cd "${WORK_DIR}/nimble"
 # nim reads nim.cfg / config.nims in the current dir, which sets vendor paths.
 "${NIM_BIN}" c -d:release --path:src \
+<<<<<<< HEAD
+  -o:"${WORK_DIR}/nimble_new${EXE}" src/nimble.nim
+
+mkdir -p "${HOME}/.nimble/bin"
+# Atomic rename: avoids ETXTBSY when the old binary at NIMBLE_BIN is still running.
+cp "${WORK_DIR}/nimble_new${EXE}" "${NIMBLE_BIN}.new.$$"
+=======
   -o:"${WORK_DIR}/nimble_new" src/nimble.nim
 
 mkdir -p "${HOME}/.nimble/bin"
 # Atomic rename: avoids ETXTBSY when the old binary at NIMBLE_BIN is still running.
 cp "${WORK_DIR}/nimble_new" "${NIMBLE_BIN}.new.$$"
+>>>>>>> master
 mv -f "${NIMBLE_BIN}.new.$$" "${NIMBLE_BIN}"
 
 echo "Nimble ${NIMBLE_VERSION} installed to ${NIMBLE_BIN}"
\ No newline at end of file