diff --git a/bootstrap_sdk b/bootstrap_sdk
index fccd6e039cf..bf094e28a79 100755
--- a/bootstrap_sdk
+++ b/bootstrap_sdk
@@ -7,9 +7,9 @@
 # This uses Gentoo's catalyst for very thoroughly building images from
 # scratch. Using images based on this will eliminate some of the hackery
 # in make_chroot.sh for building up the sdk from a stock stage3 tarball.
-# 
+#
 # For reference the procedure it performs is this:
-# 
+#
 # 1. snapshot: Grab a snapshot of the portage-stable repo from
 #     the current SDK's /var/lib/gentoo/repos/gentoo.
 #     Alternatively, check out a git ref specified via --portage-ref.
@@ -68,15 +68,14 @@ DEFINE_string stage1_overlay_path "" \
 ## Define the stage4 config template
 catalyst_stage4() {
 cat <<EOF
-target: stage4
 pkgcache_path: $BINPKGS
 stage4/packages: coreos-devel/sdk-depends
 stage4/fsscript: ${BUILD_LIBRARY_DIR}/catalyst_sdk.sh
 stage4/root_overlay: ${ROOT_OVERLAY}
-stage4/empty: /etc/portage/repos.conf /root /usr/portage /var/cache/edb
+stage4/empty: /root /var/cache/edb
 stage4/rm: /etc/machine-id /etc/resolv.conf
 EOF
-catalyst_stage_default
+catalyst_stage_default 4
 }
 
 # Switch to HTTP because early boostrap stages do not have SSL support.
@@ -118,7 +117,7 @@ cp "${BUILD_LIBRARY_DIR}/toolchain_util.sh" "${ROOT_OVERLAY}/tmp"
 #
 # No package updates must happen in stage 1, so we use the portage-stable and
 #  coreos-overlay paths included with the current SDK (from the SDK chroot's
-#  /var/lib/gentoo/repos/). "Current SDK" refers to the SDK we entered with
+#  /var/gentoo/repos/). "Current SDK" refers to the SDK we entered with
 #  'cork enter', i.e. the SDK we run ./bootstrap_sdk in.
 #
 # Using ebuilds from the above mentioned sources will ensure that stage 1 builds
@@ -148,39 +147,39 @@ stage_repo() {
     local path=${2}
     local dest=${3}
     local update_seed_file=${4}
-    local gitname="$repo"
 
-    if [ "$gitname" = "gentoo" ] ; then
-        gitname="portage-stable"
-    fi
+    mkdir "$dest/$repo"
 
     if [ -z "$path" ]; then
-        cp -R "/var/gentoo/repos/${repo}" "$dest"
-        info "Using local SDK's ebuild repo '$repo' ('$gitname') in stage 1."
+        case "$repo" in
+            portage-stable) path=gentoo ;;
+            *) path=${repo} ;;
+        esac
+        cp -R --reflink=auto "/var/gentoo/repos/${path}/"* "$dest/${repo}/"
+        info "Using local SDK's ebuild repo '$repo' in stage 1."
     else
-        mkdir "$dest/$repo"
-        cp -R "${path}/"* "$dest/${repo}/"
-        info "Using custom path '$path' for ebuild repo '$repo' ('$gitname') in stage 1."
+        cp -R --reflink=auto "${path}/"* "$dest/${repo}/"
+        info "Using custom path '$path' for ebuild repo '$repo' in stage 1."
         info "This may break stage 2. YOU HAVE BEEN WARNED. You break it, you keep it."
     fi
     (
         set -euo pipefail
         local repo_var hook name
 
-        # FLAGS_coreos_overlay for gitname coreos-overlay
-        repo_var="FLAGS_${gitname//-/_}"
+        # FLAGS_coreos_overlay for coreos-overlay
+        repo_var="FLAGS_${repo//-/_}"
         shopt -s nullglob
-        for hook in "${FLAGS_coreos_overlay}/coreos/stage1_hooks/"*"-${gitname}.sh"; do
+        for hook in "${FLAGS_coreos_overlay}/coreos/stage1_hooks/"*"-${repo}.sh"; do
             name=${hook##*/}
-            name=${name%"-${gitname}.sh"}
-            info "Invoking stage1 ${gitname} hook ${name} on ${dest}/${repo}"
+            name=${name%"-${repo}.sh"}
+            info "Invoking stage1 ${repo} hook ${name} on ${dest}/${repo}"
             "${hook}" "${dest}/${repo}" "${!repo_var}" "${update_seed_file}"
         done
     )
 }
 
 build_stage1() {
-    # First, write out the default 4-stage catalyst configuration files
+    # First, write out the default catalyst configuration files
     write_configs
 
     # Prepare local copies of both the "known-good" portage-stable and the
@@ -196,22 +195,16 @@ build_stage1() {
 
     # prepare ebuild repos for stage 1, either from the local SDK (default)
     #  or from custom paths specified via command line flags
-    stage_repo "gentoo" "${FLAGS_stage1_portage_path}" "$stage1_repos" "${update_seed_file}"
+    stage_repo "portage-stable" "${FLAGS_stage1_portage_path}" "$stage1_repos" "${update_seed_file}"
     stage_repo "coreos-overlay" "${FLAGS_stage1_overlay_path}" "$stage1_repos" "${update_seed_file}"
 
-    # Create a snapshot of "known-good" portage-stable repo copy for use in stage 1
-    #  This requires us to create a custom catalyst config to point it to the
-    #  repo copy we just created, for snapshotting.
-    catalyst_conf > "$TEMPDIR/catalyst-stage1.conf"
-    sed -i "s:^portdir.*:portdir=\"$stage1_repos/gentoo\":" \
-         "$TEMPDIR/catalyst-stage1.conf"
     # take the "portage directory" (portage-stable copy) snapshot
-    build_snapshot "${TEMPDIR}/catalyst-stage1.conf" "${FLAGS_version}-stage1"
+    build_snapshot "$stage1_repos/portage-stable" "${FLAGS_version}-stage1"
 
     # Update the stage 1 spec to use the "known-good" portage-stable snapshot
     #  and coreos-overlay copy repository versions from above.
-    sed -i -e "s/^snapshot:.*/snapshot: $FLAGS_version-stage1/" \
-           -e "s,^portage_overlay:.*,portage_overlay: $stage1_repos/coreos-overlay," \
+    sed -i -e "s/^snapshot_treeish:.*/snapshot_treeish: $FLAGS_version-stage1/" \
+           -e "s,^repos:.*,repos: $stage1_repos/coreos-overlay," \
         "$TEMPDIR/stage1.spec"
 
     # If we are to use a custom path for either ebuild repo we want to update the stage1 seed SDK
@@ -220,10 +213,11 @@ build_stage1() {
         echo "update_seed_command: --update --deep --newuse --complete-graph --rebuild-if-new-ver --rebuild-exclude cross-*-cros-linux-gnu/* sys-devel/gcc " \
             >>"$TEMPDIR/stage1.spec"
     fi
+
     rm -f "${update_seed_file}"
 
     # Finally, build stage 1
-    build_stage stage1 "$SEED" "$TEMPDIR/catalyst-stage1.conf"
+    build_stage stage1
 }
 
 if [[ "$STAGES" =~ stage1 ]]; then
diff --git a/build_library/catalyst.sh b/build_library/catalyst.sh
index ea1f6a97654..ef08aa5f8b6 100644
--- a/build_library/catalyst.sh
+++ b/build_library/catalyst.sh
@@ -55,17 +55,15 @@ DEFINE_boolean debug ${FLAGS_FALSE} "Enable verbose output from catalyst."
 catalyst_conf() {
 cat <<EOF
 # catalyst.conf
-contents="auto"
-digests="md5 sha1 sha512 whirlpool"
-hash_function="crc32"
-options="pkgcache"
+digests=["md5", "sha1", "sha512", "blake2b"]
+options=["pkgcache"]
 sharedir="/usr/share/catalyst"
 storedir="$CATALYST_ROOT"
 distdir="$DISTDIR"
 envscript="$TEMPDIR/catalystrc"
 port_logdir="$CATALYST_ROOT/log"
-portdir="$FLAGS_portage_stable"
-snapshot_cache="$CATALYST_ROOT/tmp/snapshot_cache"
+repo_basedir="/mnt/host/source/src/third_party"
+repo_name="portage-stable"
 EOF
 }
 
@@ -82,61 +80,48 @@ export ac_cv_posix_semaphores_enabled=yes
 EOF
 }
 
-repos_conf() {
-cat <<EOF
-[DEFAULT]
-main-repo = portage-stable
-
-[coreos]
-location = /var/gentoo/repos/local
-
-[portage-stable]
-location = /var/gentoo/repos/gentoo
-EOF
-}
-
 # Common values for all stage spec files
 catalyst_stage_default() {
 cat <<EOF
+target: stage$1
 subarch: $ARCH
 rel_type: $TYPE
 portage_confdir: $TEMPDIR/portage
-portage_overlay: $FLAGS_coreos_overlay
+repos: $FLAGS_coreos_overlay
+keep_repos: portage-stable coreos-overlay
 profile: $FLAGS_profile
-snapshot: $FLAGS_version
+snapshot_treeish: $FLAGS_version
 version_stamp: $FLAGS_version
 cflags: -O2 -pipe
 cxxflags: -O2 -pipe
 ldflags: -Wl,-O2 -Wl,--as-needed
+source_subpath: ${SEED}
 EOF
 }
 
 # Config values for each stage
 catalyst_stage1() {
 cat <<EOF
-target: stage1
 # stage1 packages aren't published, save in tmp
 pkgcache_path: ${TEMPDIR}/stage1-${ARCH}-packages
 update_seed: no
 EOF
-catalyst_stage_default
+catalyst_stage_default 1
 }
 
 catalyst_stage2() {
 cat <<EOF
-target: stage2
 # stage2 packages aren't published, save in tmp
 pkgcache_path: ${TEMPDIR}/stage2-${ARCH}-packages
 EOF
-catalyst_stage_default
+catalyst_stage_default 2
 }
 
 catalyst_stage3() {
 cat <<EOF
-target: stage3
 pkgcache_path: $BINPKGS
 EOF
-catalyst_stage_default
+catalyst_stage_default 3
 }
 
 catalyst_stage4() {
@@ -207,8 +192,8 @@ catalyst_init() {
     # so far so good, expand path to work with weird comparison code below
     FLAGS_seed_tarball=$(readlink -f "$FLAGS_seed_tarball")
 
-    if [[ ! "$FLAGS_seed_tarball" =~ .*\.tar\.bz2 ]]; then
-        die_notrace "Seed tarball doesn't end in .tar.bz2 :-/"
+    if [[ ! "$FLAGS_seed_tarball" =~ .\.tar\.(bz2|xz) ]]; then
+        die_notrace "Seed tarball doesn't end in .tar.bz2 or .tar.xz :-/"
     fi
 
     # catalyst is obnoxious and wants the $TYPE/stage3-$VERSION part of the
@@ -216,49 +201,41 @@ catalyst_init() {
     # directory under $TEMPDIR instead, aka the SEEDCACHE feature.)
     if [[ "$FLAGS_seed_tarball" =~ "$CATALYST_ROOT/builds/".* ]]; then
         SEED="${FLAGS_seed_tarball#$CATALYST_ROOT/builds/}"
-        SEED="${SEED%.tar.bz2}"
+        SEED="${SEED%.tar.*}"
     else
         mkdir -p "$CATALYST_ROOT/builds/seed"
         cp -n "$FLAGS_seed_tarball" "$CATALYST_ROOT/builds/seed"
         SEED="seed/${FLAGS_seed_tarball##*/}"
-        SEED="${SEED%.tar.bz2}"
+        SEED="${SEED%.tar.*}"
     fi
 }
 
 write_configs() {
     info "Creating output directories..."
-    mkdir -m 775 -p "$TEMPDIR/portage/repos.conf" "$DISTDIR"
+    mkdir -m 775 -p "$DISTDIR"
     chown portage:portage "$DISTDIR"
     info "Writing out catalyst configs..."
     info "    catalyst.conf"
     catalyst_conf > "$TEMPDIR/catalyst.conf"
     info "    catalystrc"
     catalystrc > "$TEMPDIR/catalystrc"
-    info "    portage/repos.conf/coreos.conf"
-    repos_conf > "$TEMPDIR/portage/repos.conf/coreos.conf"
     info "    stage1.spec"
     catalyst_stage1 > "$TEMPDIR/stage1.spec"
-    info "    stage2.spec"
-    catalyst_stage2 > "$TEMPDIR/stage2.spec"
-    info "    stage3.spec"
-    catalyst_stage3 > "$TEMPDIR/stage3.spec"
-    info "    stage4.spec"
-    catalyst_stage4 > "$TEMPDIR/stage4.spec"
-    info "Putting a symlink to user patches..."
-    ln -sfT '/var/gentoo/repos/local/coreos/user-patches' \
-        "$TEMPDIR/portage/patches"
+
+    info "Configuring Portage..."
+    cp -r "${BUILD_LIBRARY_DIR}"/portage/ "${TEMPDIR}/"
+
+    ln -sfT '/var/gentoo/repos/coreos-overlay/coreos/user-patches' \
+        "${TEMPDIR}"/portage/patches
 }
 
 build_stage() {
-    local stage srcpath catalyst_conf target_tarball
+    local stage catalyst_conf target_tarball
 
     stage="$1"
-    srcpath="$2"
-    catalyst_conf="$3"
+    catalyst_conf="$TEMPDIR/catalyst.conf"
     target_tarball="${stage}-${ARCH}-${FLAGS_version}.tar.bz2"
 
-    [ -z "$catalyst_conf" ] && catalyst_conf="$TEMPDIR/catalyst.conf"
-
     if [[ -f "$BUILDS/${target_tarball}" && $FLAGS_rebuild == $FLAGS_FALSE ]]
     then
         info "Skipping $stage, $target_tarball already exists."
@@ -270,8 +247,7 @@ build_stage() {
         "${DEBUG[@]}" \
         --verbose \
         --config "$TEMPDIR/catalyst.conf" \
-        --file "$TEMPDIR/${stage}.spec" \
-        --cli "source_subpath=$srcpath"
+        --file "$TEMPDIR/${stage}.spec"
     # Catalyst does not clean up after itself...
     rm -rf "$TEMPDIR/$stage-${ARCH}-${FLAGS_version}"
     ln -sf "$stage-${ARCH}-${FLAGS_version}.tar.bz2" \
@@ -280,46 +256,19 @@ build_stage() {
 }
 
 build_snapshot() {
-    local catalyst_conf snapshot snapshots_dir snapshot_base snapshot_path
+    local repo_dir snapshot snapshots_dir snapshot_path
 
-    catalyst_conf=${1:-"${TEMPDIR}/catalyst.conf"}
+    repo_dir=${1:-"${FLAGS_portage_stable}"}
     snapshot=${2:-"${FLAGS_version}"}
     snapshots_dir="${CATALYST_ROOT}/snapshots"
-    snapshot_base="${snapshots_dir}/gentoo-${snapshot}"
-    snapshot_path="${snapshot_base}.tar.bz2"
-    if [[ -f "${snapshot_path}" && $FLAGS_rebuild == $FLAGS_FALSE ]]
+    snapshot_path="${snapshots_dir}/portage-stable-${snapshot}.sqfs"
+    if [[ -f ${snapshot_path} && $FLAGS_rebuild == $FLAGS_FALSE ]]
     then
         info "Skipping snapshot, ${snapshot_path} exists"
     else
         info "Creating snapshot ${snapshot_path}"
-        catalyst \
-            "${DEBUG[@]}" \
-            --verbose \
-            --config "${catalyst_conf}" \
-            --snapshot "${snapshot}"
-    fi
-    local f
-    local to_remove=()
-    # This will expand to at least our just built snapshot tarball, so
-    # no nullglob is needed here.
-    for f in "${snapshot_base}".*; do
-        case "${f}" in
-            "${snapshot_path}")
-                # Our snapshot, keep it as is.
-                :
-                ;;
-            *.CONTENTS|*.CONTENTS.gz|*.DIGESTS)
-                # These can stay, catalyst is not bothered by those.
-                :
-                ;;
-            *)
-                to_remove+=("${f}")
-                ;;
-        esac
-    done
-    if [[ ${#to_remove[@]} -gt 0 ]]; then
-        info "$(printf '%s\n' 'Found spurious files in snapshots directory that may confuse Catalyst, removing them:' "${to_remove[@]}")"
-        rm -rf "${to_remove[@]}"
+        mkdir -p "${snapshot_path%/*}"
+        tar -c -C "${repo_dir}" . | tar2sqfs "${snapshot_path}" -q -f -j1 -c gzip
     fi
 }
 
@@ -335,7 +284,7 @@ catalyst_build() {
 
     used_seed=0
     if [[ "$STAGES" =~ stage1 ]]; then
-        build_stage stage1 "$SEED"
+        build_stage stage1
         used_seed=1
     fi
 
@@ -343,7 +292,9 @@ catalyst_build() {
         if [[ $used_seed -eq 1 ]]; then
             SEED="${TYPE}/stage1-${ARCH}-latest"
         fi
-        build_stage stage2 "$SEED"
+        info "    stage2.spec"
+        catalyst_stage2 > "$TEMPDIR/stage2.spec"
+        build_stage stage2
         used_seed=1
     fi
 
@@ -351,7 +302,9 @@ catalyst_build() {
         if [[ $used_seed -eq 1 ]]; then
             SEED="${TYPE}/stage2-${ARCH}-latest"
         fi
-        build_stage stage3 "$SEED"
+        info "    stage3.spec"
+        catalyst_stage3 > "$TEMPDIR/stage3.spec"
+        build_stage stage3
         used_seed=1
     fi
 
@@ -359,10 +312,12 @@ catalyst_build() {
         if [[ $used_seed -eq 1 ]]; then
             SEED="${TYPE}/stage3-${ARCH}-latest"
         fi
-        build_stage stage4 "$SEED"
+        info "    stage4.spec"
+        catalyst_stage4 > "$TEMPDIR/stage4.spec"
+        build_stage stage4
         used_seed=1
     fi
 
     # Cleanup snapshots, we don't use them
-    rm -rf "$CATALYST_ROOT/snapshots/gentoo-${FLAGS_version}.tar.bz2"*
+    rm -rf "$CATALYST_ROOT/snapshots/${FLAGS_portage_stable##*/}-${FLAGS_version}.sqfs"*
 }
diff --git a/build_library/catalyst_sdk.sh b/build_library/catalyst_sdk.sh
index e5fb29a188b..ff3f3d4b1d4 100644
--- a/build_library/catalyst_sdk.sh
+++ b/build_library/catalyst_sdk.sh
@@ -11,7 +11,7 @@ echo "Setting the default Python interpreter"
 eselect python update
 
 echo "Building cross toolchain for the SDK."
-configure_crossdev_overlay / /tmp/crossdev
+configure_crossdev_overlay / /usr/local/portage/crossdev
 
 for cross_chost in $(get_chost_list); do
     echo "Building cross toolchain for ${cross_chost}"
@@ -21,10 +21,11 @@ for cross_chost in $(get_chost_list); do
         install_cross_rust "${cross_chost}" ${clst_myemergeopts}
 done
 
-echo "Saving snapshot of coreos-overlay repo for future SDK bootstraps"
-# Copy coreos-overlay, which is in /var/gentoo/repos/local/, into a
-# local directory.  /var/gentoo/repos/local/ is removed before archiving
-# and we want to keep a snapshot. This snapshot is used - alongside
-# /var/gentoo/repos/gentoo - by stage 1 of future bootstraps.
-mkdir -p /var/gentoo/repos/coreos-overlay
-cp -R /var/gentoo/repos/local/* /var/gentoo/repos/coreos-overlay
+echo "Saving snapshot of repos for future SDK bootstraps"
+# Copy portage-stable and coreos-overlay, which are under
+# /mnt/host/source/src/third_party, into a local directory because they are
+# removed before archiving and we want to keep snapshots. These snapshots are
+# used by stage 1 in future bootstraps.
+mkdir -p /var/gentoo/repos/{gentoo,coreos-overlay}
+cp -R /mnt/host/source/src/third_party/portage-stable/* /var/gentoo/repos/gentoo/
+cp -R /mnt/host/source/src/third_party/coreos-overlay/* /var/gentoo/repos/coreos-overlay/
diff --git a/build_library/catalyst_toolchains.sh b/build_library/catalyst_toolchains.sh
index 0c041b3dd34..92d6e932136 100644
--- a/build_library/catalyst_toolchains.sh
+++ b/build_library/catalyst_toolchains.sh
@@ -37,7 +37,7 @@ build_target_toolchain() {
         run_merge -u --root="$ROOT" --sysroot="$ROOT" "${TOOLCHAIN_PKGS[@]}"
 }
 
-configure_crossdev_overlay / /tmp/crossdev
+configure_crossdev_overlay / /usr/local/portage/crossdev
 
 for board in $(get_board_list); do
     echo "Building native toolchain for ${board}"
diff --git a/build_library/dev_container_util.sh b/build_library/dev_container_util.sh
index a0c07477cd1..3d702c32eb1 100755
--- a/build_library/dev_container_util.sh
+++ b/build_library/dev_container_util.sh
@@ -42,22 +42,24 @@ PORTAGE_BINHOST="$(get_binhost_url "${binhost}" "${update_group}" 'pkgs')
 $(get_binhost_url "${binhost}" "${update_group}" 'toolchain')"
 EOF
 
-    sudo_clobber "${root_fs_dir}/etc/portage/repos.conf/coreos.conf" <<EOF
+    sudo_clobber "${root_fs_dir}/etc/portage/repos.conf/portage-stable.conf" <<EOF
 [DEFAULT]
 main-repo = portage-stable
 
-[coreos]
-location = /var/lib/portage/coreos-overlay
-
 [portage-stable]
 location = /var/lib/portage/portage-stable
+EOF
+
+    sudo_clobber "${root_fs_dir}/etc/portage/repos.conf/coreos-overlay.conf" <<EOF
+[coreos-overlay]
+location = /var/lib/portage/coreos-overlay
 EOF
 
     # Now set the correct profile, we do not use the eselect tool - it
     # does not seem to be usable outside of the chroot without using
     # deprecated PORTDIR and PORTDIR_OVERLAY environment variables.
     local profile_name=$(get_board_profile "${BOARD}")
-    # Turn coreos:coreos/amd64/generic into coreos/amd64/generic/dev
+    # Turn coreos-overlay:coreos/amd64/generic into coreos/amd64/generic/dev
     profile_name="${profile_name#*:}/dev"
     local profile_directory="${root_fs_dir}/var/lib/portage/coreos-overlay/profiles/${profile_name}"
     if [[ ! -d "${profile_directory}" ]]; then
diff --git a/build_library/portage/profile/package.use.force/releng/alternatives b/build_library/portage/profile/package.use.force/releng/alternatives
new file mode 100644
index 00000000000..1162dfda86d
--- /dev/null
+++ b/build_library/portage/profile/package.use.force/releng/alternatives
@@ -0,0 +1,10 @@
+# need this here because of stage1
+app-alternatives/awk gawk
+app-alternatives/bc gnu
+app-alternatives/bzip2 reference
+app-alternatives/cpio gnu
+app-alternatives/gzip reference
+app-alternatives/lex flex
+app-alternatives/sh bash
+app-alternatives/tar gnu
+app-alternatives/yacc bison
diff --git a/build_library/toolchain_util.sh b/build_library/toolchain_util.sh
index 8afd45e49f3..65848e91309 100644
--- a/build_library/toolchain_util.sh
+++ b/build_library/toolchain_util.sh
@@ -14,18 +14,18 @@ TOOLCHAIN_PKGS=(
 # This is only used as an intermediate step to be able to use the cross
 # compiler to build a full native toolchain. Packages are not uploaded.
 declare -A CROSS_PROFILES
-CROSS_PROFILES["x86_64-cros-linux-gnu"]="coreos:coreos/amd64/generic"
-CROSS_PROFILES["aarch64-cros-linux-gnu"]="coreos:coreos/arm64/generic"
+CROSS_PROFILES["x86_64-cros-linux-gnu"]="coreos-overlay:coreos/amd64/generic"
+CROSS_PROFILES["aarch64-cros-linux-gnu"]="coreos-overlay:coreos/arm64/generic"
 
 # Map board names to CHOSTs and portage profiles. This is the
 # definitive list, there is assorted code new and old that either
 # guesses or hard-code these. All that should migrate to this list.
 declare -A BOARD_CHOSTS BOARD_PROFILES
 BOARD_CHOSTS["amd64-usr"]="x86_64-cros-linux-gnu"
-BOARD_PROFILES["amd64-usr"]="coreos:coreos/amd64/generic"
+BOARD_PROFILES["amd64-usr"]="coreos-overlay:coreos/amd64/generic"
 
 BOARD_CHOSTS["arm64-usr"]="aarch64-cros-linux-gnu"
-BOARD_PROFILES["arm64-usr"]="coreos:coreos/arm64/generic"
+BOARD_PROFILES["arm64-usr"]="coreos-overlay:coreos/arm64/generic"
 
 BOARD_NAMES=( "${!BOARD_CHOSTS[@]}" )
 
@@ -169,7 +169,7 @@ get_sdk_arch() {
 }
 
 get_sdk_profile() {
-    echo "coreos:coreos/$(get_sdk_arch)/sdk"
+    echo "coreos-overlay:coreos/$(get_sdk_arch)/sdk"
 }
 
 get_sdk_libdir() {
@@ -244,7 +244,7 @@ configure_crossdev_overlay() {
     echo "x-crossdev" | \
         "${sudo[@]}" tee "${root}${location}/profiles/repo_name" > /dev/null
     "${sudo[@]}" tee "${root}${location}/metadata/layout.conf" > /dev/null <<EOF
-masters = portage-stable coreos
+masters = portage-stable coreos-overlay
 use-manifests = true
 thin-manifests = true
 EOF
@@ -271,7 +271,7 @@ _get_dependency_list() {
 
 # Configure a new ROOT
 # Values are copied from the environment or the current host configuration.
-# Usage: CBUILD=foo-bar-linux-gnu ROOT=/foo/bar SYSROOT=/foo/bar configure_portage coreos:some/profile
+# Usage: CBUILD=foo-bar-linux-gnu ROOT=/foo/bar SYSROOT=/foo/bar configure_portage coreos-overlay:some/profile
 # Note: if using portageq to get CBUILD it must be called before CHOST is set.
 _configure_sysroot() {
     local profile="$1"
@@ -287,7 +287,7 @@ _configure_sysroot() {
     "${sudo[@]}" eselect profile set --force "$profile"
 
     local coreos_path
-    coreos_path=$(portageq get_repo_path "${ROOT}" coreos)
+    coreos_path=$(portageq get_repo_path "${ROOT}" coreos-overlay)
     "${sudo[@]}" ln -sfT "${coreos_path}/coreos/user-patches" "${ROOT}/etc/portage/patches"
 
     echo "Writing make.conf for the sysroot ${SYSROOT}, root ${ROOT}"
diff --git a/build_library/vm_image_util.sh b/build_library/vm_image_util.sh
index b067362fc93..ecaa792d5a5 100644
--- a/build_library/vm_image_util.sh
+++ b/build_library/vm_image_util.sh
@@ -553,7 +553,7 @@ install_oem_sysext() {
         --metapkgs="${metapkg}"
     )
     local overlay_path mangle_fs
-    overlay_path=$(portageq get_repo_path / coreos)
+    overlay_path=$(portageq get_repo_path / coreos-overlay)
     mangle_fs="${overlay_path}/${metapkg}/files/manglefs.sh"
     if [[ -x "${mangle_fs}" ]]; then
         build_sysext_flags+=(
diff --git a/build_toolchains b/build_toolchains
index ebef08c8cfc..910e797b33c 100755
--- a/build_toolchains
+++ b/build_toolchains
@@ -18,13 +18,12 @@ FORCE_STAGES="stage4"
 ## Define the stage4 config template
 catalyst_stage4() {
 cat <<EOF
-target: stage4
 pkgcache_path: $BINPKGS
 stage4/packages: @system
 stage4/fsscript: ${BUILD_LIBRARY_DIR}/catalyst_toolchains.sh
 stage4/root_overlay: ${ROOT_OVERLAY}
 EOF
-catalyst_stage_default
+catalyst_stage_default 4
 }
 create_provenance_overlay() {
   local root_overlay="$1"
diff --git a/sdk_container/src/third_party/coreos-overlay/profiles/coreos/base/package.accept_keywords b/sdk_container/src/third_party/coreos-overlay/profiles/coreos/base/package.accept_keywords
index 5e216c42b09..0e2113c44d3 100644
--- a/sdk_container/src/third_party/coreos-overlay/profiles/coreos/base/package.accept_keywords
+++ b/sdk_container/src/third_party/coreos-overlay/profiles/coreos/base/package.accept_keywords
@@ -7,6 +7,9 @@
 # Gentoo upstream package stabilisation
 # (the following packages are "unstable" upstream; we're stabilising these)
 
+# Catalyst 4 is not stable yet, but earlier versions are masked now.
+dev-util/catalyst ~amd64 ~arm64
+
 =app-containers/containerd-1.7.19 ~amd64 ~arm64 # DO NOT EDIT THIS LINE. Added by containerd-apply-patch.sh on 2024-07-05 08:17:23
 =app-containers/cri-tools-1.27.0 ~amd64 ~arm64
 =app-containers/runc-1.1.13 ~amd64 ~arm64
diff --git a/sdk_container/src/third_party/coreos-overlay/profiles/coreos/base/package.unmask b/sdk_container/src/third_party/coreos-overlay/profiles/coreos/base/package.unmask
index 1d33cf13b19..7eebbb56b18 100644
--- a/sdk_container/src/third_party/coreos-overlay/profiles/coreos/base/package.unmask
+++ b/sdk_container/src/third_party/coreos-overlay/profiles/coreos/base/package.unmask
@@ -2,7 +2,3 @@
 # with rust so far, so keep using 1.70.0.
 ~dev-lang/rust-1.79.0
 ~virtual/rust-1.79.0
-
-# portage-stable masked catalyst-3, and has not provided a stable way to
-# update to catalyst-4 so overriding the change for now to use catalyst-3
-<dev-util/catalyst-4
diff --git a/sdk_container/src/third_party/coreos-overlay/profiles/coreos/base/package.use.mask b/sdk_container/src/third_party/coreos-overlay/profiles/coreos/base/package.use.mask
index 85f795b138e..a3bbe7766d9 100644
--- a/sdk_container/src/third_party/coreos-overlay/profiles/coreos/base/package.use.mask
+++ b/sdk_container/src/third_party/coreos-overlay/profiles/coreos/base/package.use.mask
@@ -1,8 +1,8 @@
 # We don't ship GnuTLS by default, and smartcard has a dep loop
 app-crypt/gnupg smartcard ssl
 
-# not needed, requires dev-lang/python-exec
-sys-apps/util-linux python
+# Our ISOs are not built with Catalyst.
+dev-util/catalyst iso
 
 # not needed, requires lots of Perl
 sys-boot/syslinux perl
diff --git a/sdk_container/src/third_party/coreos-overlay/profiles/coreos/targets/generic/package.use.mask b/sdk_container/src/third_party/coreos-overlay/profiles/coreos/targets/generic/package.use.mask
new file mode 100644
index 00000000000..0251dc55915
--- /dev/null
+++ b/sdk_container/src/third_party/coreos-overlay/profiles/coreos/targets/generic/package.use.mask
@@ -0,0 +1,2 @@
+# Only needed by Catalyst in the SDK, requires dev-lang/python-exec.
+sys-apps/util-linux python
diff --git a/sdk_container/src/third_party/coreos-overlay/profiles/coreos/targets/sdk/package.use b/sdk_container/src/third_party/coreos-overlay/profiles/coreos/targets/sdk/package.use
index 82cd27b1a9b..27049b2d914 100644
--- a/sdk_container/src/third_party/coreos-overlay/profiles/coreos/targets/sdk/package.use
+++ b/sdk_container/src/third_party/coreos-overlay/profiles/coreos/targets/sdk/package.use
@@ -1,3 +1,6 @@
+# Needed by Catalyst.
+sys-apps/util-linux python
+
 coreos-base/update_engine delta_generator
 
 dev-vcs/git pcre
diff --git a/sdk_container/src/third_party/coreos-overlay/profiles/repo_name b/sdk_container/src/third_party/coreos-overlay/profiles/repo_name
index e76bc6a4057..cf96a73002d 100644
--- a/sdk_container/src/third_party/coreos-overlay/profiles/repo_name
+++ b/sdk_container/src/third_party/coreos-overlay/profiles/repo_name
@@ -1 +1 @@
-coreos
+coreos-overlay
diff --git a/sdk_container/src/third_party/portage-stable/metadata/layout.conf b/sdk_container/src/third_party/portage-stable/metadata/layout.conf
index da12d64d54b..b507dd6f614 100644
--- a/sdk_container/src/third_party/portage-stable/metadata/layout.conf
+++ b/sdk_container/src/third_party/portage-stable/metadata/layout.conf
@@ -1,4 +1,3 @@
-repo-name = portage-stable
 use-manifests = strict
 thin-manifests = true
 cache-format = md5-dict
diff --git a/sdk_container/src/third_party/portage-stable/profiles/repo_name b/sdk_container/src/third_party/portage-stable/profiles/repo_name
index 23574f35785..316c11ecc49 100644
--- a/sdk_container/src/third_party/portage-stable/profiles/repo_name
+++ b/sdk_container/src/third_party/portage-stable/profiles/repo_name
@@ -1 +1 @@
-gentoo
+portage-stable
diff --git a/setup_board b/setup_board
index ecc689decfe..bba9251ab7e 100755
--- a/setup_board
+++ b/setup_board
@@ -233,7 +233,7 @@ fi
 
 info "Configuring portage in ${BOARD_ROOT}"
 sudo mkdir -p "${BOARD_ETC}/portage/"{profile,repos.conf}
-sudo ln -sfT "$(portageq get_repo_path / coreos)/coreos/user-patches" \
+sudo ln -sfT "$(portageq get_repo_path / coreos-overlay)/coreos/user-patches" \
    "${BOARD_ETC}/portage/patches"
 sudo cp /etc/portage/repos.conf/* "${BOARD_ETC}"/portage/repos.conf/
 sudo ROOT="${BOARD_ROOT}" eselect profile set --force "${PORTAGE_PROFILE}"
diff --git a/update_chroot b/update_chroot
index af57a729b58..2a9cbeb3212 100755
--- a/update_chroot
+++ b/update_chroot
@@ -103,17 +103,19 @@ EMERGE_DEFAULT_OPTS="--verbose --oneshot"
 source "/etc/portage/make.conf.user"
 EOF
 
-sudo_clobber "/etc/portage/repos.conf/coreos.conf" <<EOF
+sudo_clobber "/etc/portage/repos.conf/portage-stable.conf" <<EOF
 [DEFAULT]
 main-repo = portage-stable
 
-[coreos]
-location = ${COREOS_OVERLAY}
-
 [portage-stable]
 location = ${PORTAGE_STABLE_OVERLAY}
 EOF
 
+sudo_clobber "/etc/portage/repos.conf/coreos-overlay.conf" <<EOF
+[coreos-overlay]
+location = ${COREOS_OVERLAY}
+EOF
+
 # Automatically symlink any provided portage repo configurations into
 # the appropriate destination directory from "config/portage/repos".
 # CAUTON: Any repo configuration files with the same name, will be silently
@@ -132,13 +134,13 @@ if [[ -n $(sudo find /mnt/host/source/config/portage/repos \
   if [[ -n $(sudo find /mnt/host/source/config/portage/repos \
     -maxdepth 3 -mindepth 3 -path "*/repos.conf/*" -type f) ]]; then
     info "Symlinking portage repo configuration files into repos.conf dir..."
-    # Do not name any of your repo configs "coreos.conf" bad things will happen.
-    # We abort if any file matches config/portage/repos/*/repos.conf/coreos.conf
+    # Do not name any of your repo configs "coreos-overlay.conf" bad things will happen.
+    # We abort if any file matches config/portage/repos/*/repos.conf/coreos-overlay.conf
     if [[ -n $(sudo find /mnt/host/source/config/portage/repos \
-      -maxdepth 3 -mindepth 3 -path "*/repos.conf/*" -name "coreos.conf") ]]; then
+      -maxdepth 3 -mindepth 3 -path "*/repos.conf/*" -name "coreos-overlay.conf") ]]; then
       die_notrace "One of the portage repo configuration files to be symlinked is " \
-        "named \"coreos.conf\" which will conflict with the main configuation file " \
-        "called \"coreos.conf\" which is created during the chroot build process."
+        "named \"coreos-overlay.conf\" which will conflict with the main configuation file " \
+        "called \"coreos-overlay.conf\" which is created during the chroot build process."
     fi
     # We run through all the other files matching config/portage/repos/*/repos.conf/*
     # and symlink them to the right place for portage.
diff --git a/update_distfiles b/update_distfiles
index 5f0bea0cdef..00abd37fab8 100755
--- a/update_distfiles
+++ b/update_distfiles
@@ -26,7 +26,7 @@ eval set -- "${FLAGS_ARGV}"
 switch_to_strict_mode
 
 if [[ $# -eq 0 ]]; then
-    eval set -- portage-stable coreos
+    eval set -- portage-stable coreos-overlay
 fi
 
 GSUTIL_OPTS=
diff --git a/update_metadata b/update_metadata
index 22add591585..fd9972d4fd5 100755
--- a/update_metadata
+++ b/update_metadata
@@ -16,7 +16,7 @@ eval set -- "${FLAGS_ARGV}"
 switch_to_strict_mode
 
 if [[ $# -eq 0 ]]; then
-    eval set -- portage-stable coreos
+    eval set -- portage-stable coreos-overlay
 fi
 
 update_overlay() {