diff --git a/image-recipe/_archived/build-auto-installer-iso.sh b/image-recipe/_archived/build-auto-installer-iso.sh
index 75684ad6..bdcd18ed 100755
--- a/image-recipe/_archived/build-auto-installer-iso.sh
+++ b/image-recipe/_archived/build-auto-installer-iso.sh
@@ -1353,9 +1353,11 @@ if [ "$UNBUNDLED" = "1" ]; then
     # unbundled mode — their images must ride on the ISO so a fresh install
     # works with no internet: FileBrowser (Cloud file manager) and fmcd
     # (fedimint-clientd, ecash/sats out of the box).
+    # Shipped zstd-compressed: podman load auto-detects compression, and an
+    # uncompressed fmcd.tar alone added ~220MB to the ISO (RC9 size regression).
     CORE_BUNDLE="
-${FILEBROWSER_IMAGE} filebrowser.tar
-${FMCD_IMAGE} fmcd.tar
+${FILEBROWSER_IMAGE} filebrowser.tar.zst
+${FMCD_IMAGE} fmcd.tar.zst
 "
     echo "$CORE_BUNDLE" | while read -r CORE_IMAGE CORE_FILE; do
         [ -n "$CORE_IMAGE" ] || continue
@@ -1364,9 +1366,14 @@ ${FMCD_IMAGE} fmcd.tar
         else
             echo "   Pulling $CORE_IMAGE ($CONTAINER_PLATFORM)..."
             if container_pull "$CORE_IMAGE"; then
-                $CONTAINER_CMD save "$CORE_IMAGE" -o "$IMAGES_DIR/$CORE_FILE" 2>/dev/null && \
-                    echo "   ✅ Saved core: $CORE_FILE ($(du -h "$IMAGES_DIR/$CORE_FILE" | cut -f1))" || \
+                RAW_TAR="$IMAGES_DIR/${CORE_FILE%.zst}"
+                if $CONTAINER_CMD save "$CORE_IMAGE" -o "$RAW_TAR" 2>/dev/null && \
+                    zstd -q -T0 -15 --rm "$RAW_TAR" -o "$IMAGES_DIR/$CORE_FILE"; then
+                    echo "   ✅ Saved core: $CORE_FILE ($(du -h "$IMAGES_DIR/$CORE_FILE" | cut -f1))"
+                else
+                    rm -f "$RAW_TAR" "$IMAGES_DIR/$CORE_FILE"
                     echo "   ⚠️  Failed to save $CORE_IMAGE"
+                fi
             else
                 echo "   ⚠️  Failed to pull $CORE_IMAGE — baseline app won't work offline"
             fi
@@ -1509,7 +1516,7 @@ done
 PODMAN="runuser -u archipelago -- env XDG_RUNTIME_DIR=/run/user/$ARCH_UID podman"
 $PODMAN system migrate >> "$LOG_FILE" 2>&1 || true
 
-for tarfile in "$IMAGES_DIR"/*.tar; do
+for tarfile in "$IMAGES_DIR"/*.tar "$IMAGES_DIR"/*.tar.zst; do
     if [ -f "$tarfile" ]; then
         echo "$(date): Loading $(basename "$tarfile")..." >> "$LOG_FILE"
         $PODMAN load -i "$tarfile" >> "$LOG_FILE" 2>&1 && \
@@ -2520,7 +2527,7 @@ fi
 if [ -d "$BOOT_MEDIA/archipelago/container-images" ]; then
     echo "   Copying container images (this may take a moment)..."
     mkdir -p /mnt/target/opt/archipelago/container-images
-    cp -r "$BOOT_MEDIA/archipelago/container-images/"*.tar /mnt/target/opt/archipelago/container-images/ 2>/dev/null || true
+    cp -r "$BOOT_MEDIA/archipelago/container-images/"*.tar* /mnt/target/opt/archipelago/container-images/ 2>/dev/null || true
     
     # Copy first-boot loader script and service
     mkdir -p /mnt/target/opt/archipelago/scripts