diff --git a/xbps-src b/xbps-src
index f66634ea23..e88593d734 100755
--- a/xbps-src
+++ b/xbps-src
@@ -216,22 +216,6 @@ check_config_vars() {
     fi
 }
 
-create_temporary_masterdir() {
-    if [ -n "$IN_CHROOT" -o -z "$XBPS_TEMP_MASTERDIR" ]; then
-        return
-    fi
-    XBPS_TEMP_MASTERDIR=$(mktemp -d -q -p $XBPS_DISTDIR masterdir.XXXXXXXXX || exit 1)
-
-    cp -a $XBPS_MASTERDIR/* $XBPS_TEMP_MASTERDIR/
-    if [ $? -ne 0 ]; then
-        echo "ERROR: failed to setup temporary masterdir $XBPS_TEMP_MASTERDIR!"
-        exit 1
-    fi
-    export CHROOT_READY=1
-    export XBPS_MASTERDIR=$XBPS_TEMP_MASTERDIR
-}
-
-
 check_build_requirements() {
     local found
 
@@ -525,6 +509,15 @@ for i in REPOSITORY DESTDIR BUILDDIR SRCDISTDIR; do
     unset val
 done
 
+# A temporary masterdir requires xbps-uchroot(8) and -O to use overlayfs
+# on tmpfs (available with xbps-0.45).
+if [ -n "$XBPS_TEMP_MASTERDIR" ]; then
+    if [ "$XBPS_CHROOT_CMD" != "uchroot" ]; then
+        echo "ERROR: -t requires XBPS_CHROOT_CMD=uchroot, exiting..."
+        exit 1
+    fi
+    export XBPS_CHROOT_CMD_ARGS="-O"
+fi
 #
 # Sanitize PATH.
 #
@@ -618,10 +611,6 @@ case "$XBPS_TARGET" in
         ;;
     fetch|extract|build|configure|install|pkg)
         read_pkg
-        if [ -n "$XBPS_TEMP_MASTERDIR" ]; then
-            bootstrap_update
-            create_temporary_masterdir
-        fi
         if [ -n "$CHROOT_READY" -a -z "$IN_CHROOT" ]; then
             chroot_handler $XBPS_TARGET $XBPS_TARGET_PKG
         else