diff --git a/build_library/build_image_util.sh b/build_library/build_image_util.sh
index 242e8b9432..da266d42f6 100755
--- a/build_library/build_image_util.sh
+++ b/build_library/build_image_util.sh
@@ -265,12 +265,15 @@ query_available_package() {
             tail -n 1
 }
 
-# Generate a list of packages installed in an image.
-# Usage: image_packages /image/root
-image_packages() {
-    local profile="${BUILD_DIR}/configroot/etc/portage/profile"    
+# List packages installed directly in portages package database
+image_packages_portage() {
     ROOT="$1" PORTAGE_CONFIGROOT="${BUILD_DIR}"/configroot \
         equery --no-color list --format '$cpv::$repo' '*'
+}
+# List packages implicitly contained in rootfs, such as in torcx packages or
+# initramfs.
+image_packages_implicit() {
+    local profile="${BUILD_DIR}/configroot/etc/portage/profile"
 
     # We also want to list packages that only exist in the initramfs.
     # Approximate this by listing build dependencies of coreos-kernel that
@@ -304,6 +307,13 @@ image_packages() {
     while read pkg ; do query_available_package "${pkg}" ; done
 }
 
+# Generate a list of packages installed in an image.
+# Usage: image_packages /image/root
+image_packages() {
+  image_packages_portage "$1"
+  image_packages_implicit "$1"
+}
+
 # Generate a list of installed packages in the format:
 #   sys-apps/systemd-212-r8::coreos
 write_packages() {
@@ -517,6 +527,35 @@ EOF
     sudo gzip -9 "${root_fs_dir}"/usr/share/licenses/common/*
 }
 
+# Add /usr/share/SLSA reports for packages indirectly contained within the rootfs
+# If the package is available in BOARD_ROOT accesses it from there, otherwise
+# needs to download binpkg.
+# Reports for torcx packages are also included when adding the torcx package to
+# rootfs.
+insert_extra_slsa() {
+  info "Inserting additional SLSA file"
+  local rootfs="$1"
+  for atom in $(image_packages_implicit "$rootfs"); do
+    pkg="${atom%::*}"
+    pkg="${pkg/\//_}.json.xz"
+    if [ -f "${BOARD_ROOT}/usr/share/SLSA/${pkg}" ]; then
+      info "Found ${atom} in BOARD_ROOT"
+      sudo cp "${BOARD_ROOT}/usr/share/SLSA/${pkg}" "${rootfs}/usr/share/SLSA/"
+      continue
+    fi
+    # let's not die if SLSA information is missing
+    pkgversion=$( (get_binary_pkg "=${atom}" 2>/dev/null ) || true)
+    binpkg="$(portageq-${BOARD} pkgdir)/${pkgversion}.tbz2"
+    if [ -f "${binpkg}" ]; then
+      info "Found ${atom} at ${binpkg}"
+      qtbz2 -O -t "${binpkg}" | \
+        sudo tar -C "${rootfs}" -xj --wildcards './usr/share/SLSA'
+      continue
+    fi
+    warn "Missing SLSA information for ${atom}"
+  done
+}
+
 # Add an entry to the image's package.provided
 package_provided() {
     local p profile="${BUILD_DIR}/configroot/etc/portage/profile"    
@@ -606,7 +645,7 @@ finish_image() {
           local casDigest="$(torcx_manifest::get_digest "${FLAGS_torcx_manifest}" "${pkg}" "${version}")"
           sudo cp "${FLAGS_torcx_root}/pkgs/${BOARD}/${pkg}/${casDigest}/${pkg}:${version}.torcx.tgz" \
             "${root_fs_dir}${on_disk_path}"
-
+          sudo tar xf "${root_fs_dir}${on_disk_path}" -C "${root_fs_dir}" --wildcards "./usr/share/SLSA"
           if [[ "${version}" == "${default_version}" ]]; then
             # Create the default symlink for this package
             sudo ln -fns "${on_disk_path##*/}" \
diff --git a/build_library/prod_image_util.sh b/build_library/prod_image_util.sh
index 9ffa81108b..77502402bb 100755
--- a/build_library/prod_image_util.sh
+++ b/build_library/prod_image_util.sh
@@ -46,7 +46,8 @@ extract_prod_gcc() {
     qtbz2 -O -t "${pkg}" | \
         sudo tar -C "${root_fs_dir}" -xj \
         --transform 's#/usr/lib/.*/#/usr/lib64/#' \
-        --wildcards './usr/lib/gcc/*.so*'
+        --wildcards './usr/lib/gcc/*.so*' \
+        --wildcards './usr/share/SLSA'
 
     package_provided "${gcc}"
 }
@@ -85,6 +86,7 @@ create_prod_image() {
   write_sbom "${root_fs_dir}" "${BUILD_DIR}/${image_sbom}"
   write_licenses "${root_fs_dir}" "${BUILD_DIR}/${image_licenses}"
   insert_licenses "${BUILD_DIR}/${image_licenses}" "${root_fs_dir}"
+  insert_extra_slsa "${root_fs_dir}"
 
   # Assert that if this is supposed to be an official build that the
   # official update keys have been used.
diff --git a/build_library/toolchain_util.sh b/build_library/toolchain_util.sh
index 7315ef6780..749b63267c 100644
--- a/build_library/toolchain_util.sh
+++ b/build_library/toolchain_util.sh
@@ -262,8 +262,9 @@ _get_dependency_list() {
 
     PORTAGE_CONFIGROOT="$ROOT" emerge "$@" --pretend \
         --emptytree --root-deps=rdeps --onlydeps --quiet | \
+        egrep "$ROOT" |
         sed -e 's/[^]]*\] \([^ :]*\).*/=\1/' |
-        egrep -v "(=$(echo "${pkgs[*]}")-[0-9])"
+        egrep -v "=($(echo "${pkgs[*]}"))-[0-9]"
 }
 
 # Configure a new ROOT
@@ -288,6 +289,8 @@ $(portageq envvar -v CHOST CBUILD ROOT \
     PORTDIR PORTDIR_OVERLAY DISTDIR PKGDIR)
 HOSTCC=\${CBUILD}-gcc
 PKG_CONFIG_PATH="\${SYSROOT}/usr/lib/pkgconfig/"
+# Enable provenance reporting by default. Produced files are in /usr/share/SLSA
+GENERATE_SLSA_PROVENANCE="true"
 EOF
 }
 
@@ -392,7 +395,7 @@ install_cross_libs() {
     # In order to get a dependency list we must calculate it before
     # updating package.provided. Otherwise portage will no-op.
     $sudo rm -f "${package_provided}/cross-${cross_chost}"
-    local cross_deps=$(ROOT="$ROOT" _get_dependency_list \
+    local cross_deps=$(ROOT="$ROOT" SYSROOT="$ROOT" _get_dependency_list \
         "$@" "${TOOLCHAIN_PKGS[@]}" | $sudo tee \
         "$ROOT/etc/portage/cross-${cross_chost}-depends")
 
diff --git a/build_toolchains b/build_toolchains
index 4168c01a10..ebef08c8cf 100755
--- a/build_toolchains
+++ b/build_toolchains
@@ -26,6 +26,24 @@ stage4/root_overlay: ${ROOT_OVERLAY}
 EOF
 catalyst_stage_default
 }
+create_provenance_overlay() {
+  local root_overlay="$1"
+  while read f; do
+    d="${f%/*}"
+    mkdir -p "${root_overlay}${d}/"
+    cp "${f}" "${root_overlay}${d}/"
+  done < <(find /mnt/host/source/src/scripts -name HEAD)
+  local scripts_git=/mnt/host/source/src/scripts/.git
+  # `git rev-parse` fails due to the safe.directory setting in SDK container.
+  # Open-code the ref lookup
+  read scripts_hash <"${scripts_git}/HEAD"
+  if [[ "${scripts_hash}" == "ref:"* ]]; then
+    read scripts_hash<"${scripts_git}/${scripts_hash#ref: }"
+    echo "${scripts_hash}" >"${root_overlay}${scripts_git}/HEAD"
+  fi
+  mkdir -p "${root_overlay}/mnt/host/source/.repo/manifests"
+  cp "${REPO_MANIFESTS_DIR}/version.txt" "${root_overlay}/mnt/host/source/.repo/manifests"
+}
 
 catalyst_init "$@"
 check_gsutil_opts
@@ -35,6 +53,7 @@ ROOT_OVERLAY="${TEMPDIR}/stage4-${ARCH}-$FLAGS_version-overlay"
 # toolchain_util.sh is required by catalyst_toolchains.sh
 mkdir -p "${ROOT_OVERLAY}/tmp"
 cp "${BUILD_LIBRARY_DIR}/toolchain_util.sh" "${ROOT_OVERLAY}/tmp"
+create_provenance_overlay "${ROOT_OVERLAY}"
 
 catalyst_build
 
diff --git a/setup_board b/setup_board
index bddb4dfcc6..c6fc42a652 100755
--- a/setup_board
+++ b/setup_board
@@ -269,6 +269,9 @@ PORTAGE_BINHOST="${BOARD_BINHOST}"
 # You can use --select to override this.
 EMERGE_DEFAULT_OPTS="--oneshot"
 
+# Enable provenance reporting by default. Produced files are in /usr/share/SLSA
+GENERATE_SLSA_PROVENANCE="true"
+
 # Allow the user to override or define additional settings.
 source "${BOARD_ETC}/portage/make.conf.user"
 EOF
@@ -319,9 +322,9 @@ if [[ ${FLAGS_regen_configs} -eq ${FLAGS_FALSE} ]]; then
     install_cross_libs "${BOARD_CHOST}" ${EMERGE_FLAGS} --buildpkg=n
 
     info "Building toolchain dependencies"
-    "${EMERGE_WRAPPER}" --buildpkg --buildpkgonly --onlydeps -e \
+    "${EMERGE_WRAPPER}" --buildpkg --buildpkgonly \
         --root="/usr/${BOARD_CHOST}" --sysroot="/usr/${BOARD_CHOST}" \
-        ${EMERGE_TOOLCHAIN_FLAGS} "${TOOLCHAIN_PKGS[@]}"
+        ${EMERGE_TOOLCHAIN_FLAGS} $(< "/usr/${BOARD_CHOST}/etc/portage/cross-${BOARD_CHOST}-depends")
     info "Building toolchain"
     "${EMERGE_WRAPPER}" --buildpkg --buildpkgonly \
         --root="/usr/${BOARD_CHOST}" --sysroot="/usr/${BOARD_CHOST}" \