diff --git a/scripts/serve-frank-primary.sh b/scripts/serve-frank-primary.sh
index 2672e78..3190ded 100755
--- a/scripts/serve-frank-primary.sh
+++ b/scripts/serve-frank-primary.sh
@@ -95,7 +95,11 @@ if [ ! -f "$FRANK_PRIMARY_TEMPLATE" ]; then
     exit 1
 fi
 
-mkdir -p "$FRANK_PRIMARY_STATE_DIR"
+mkdir -p "$FRANK_PRIMARY_STATE_DIR/kvcache/frank-primary"
+# The engine's create is NOT recursive: with only the state dir mounted, its
+# "cannot create /data/kvcache/frank-primary: No such file or directory"
+# left the SSD prefix tier off (measured 2026-10-06 boot ledger). Pre-create
+# the full path on the host so the tier opens on first boot.
 
 if [ ! -e /dev/kfd ] || [ ! -d /dev/dri ]; then
     echo "ERROR: GPU device nodes absent (/dev/kfd, /dev/dri)" >&2