diff --git a/app/CMakeLists.txt b/app/CMakeLists.txt
index 832d4eb12098..b66ab5b0735e 100644
--- a/app/CMakeLists.txt
+++ b/app/CMakeLists.txt
@@ -2,6 +2,19 @@
 
 cmake_minimum_required(VERSION 3.21.0)
 
+# Board specific overlays (these must be before find_package(Zephyr))
+# -------------------------------------------------------------------
+
+# Intel PTL: if "os_linux_overlay" used, also add "ll_userspace_overlay"
+if(DEFINED EXTRA_CONF_FILE AND (BOARD MATCHES "/ptl" OR BOARD_QUALIFIERS MATCHES "/ptl"))
+  string(FIND "${EXTRA_CONF_FILE}" "os_linux_overlay" _linux_overlay_idx)
+  string(FIND "${EXTRA_CONF_FILE}" "ll_userspace_overlay" _ll_overlay_idx)
+  if(_linux_overlay_idx GREATER_EQUAL 0 AND _ll_overlay_idx LESS 0)
+    list(APPEND EXTRA_CONF_FILE
+      "${CMAKE_CURRENT_SOURCE_DIR}/overlays/ptl/ll_userspace_overlay.conf")
+  endif()
+endif()
+
 find_package(Zephyr HINTS $ENV{ZEPHYR_BASE})
 project(sample_sof)
 
diff --git a/app/overlays/ptl/ll_userspace_overlay.conf b/app/overlays/ptl/ll_userspace_overlay.conf
index 8b21815e51b9..a74ef5563f29 100644
--- a/app/overlays/ptl/ll_userspace_overlay.conf
+++ b/app/overlays/ptl/ll_userspace_overlay.conf
@@ -1,7 +1,8 @@
 # This is overlay configuration file to enable user-space LL audio
-# pipeline support. This overlay is intended for development
-# purposes. If user-space LL is enabled for some build target by
-# default, the settings should be made in the SOF board file directly.
+# pipeline support.
+#
+# NOTE: this overlay is automatically included if PTL is built
+#       with generic "os_linux_overlay.conf"
 
 # Enable user-space LL support in SOF
 # -----------------------------------
@@ -36,10 +37,12 @@ CONFIG_XRUN_NOTIFICATIONS_ENABLE=n
 # max two isolated DP modules
 CONFIG_XTENSA_MMU_NUM_L2_TABLES=70
 
-# Extend the shared LL user-space heap to 512KiB. This
-# is current maximum for PTL builds with virtual heap
-# enabled and uses the vmh allocation intended for KBP.
-# TODO: needs some better solution to allocate
-CONFIG_SOF_ZEPHYR_SYS_USER_HEAP_SIZE=0x80000
-
+# Allocate majority of heap to user-space but only
+# via vregions.
+CONFIG_SOF_ZEPHYR_SYS_USER_HEAP_SIZE=0x40000
+CONFIG_SOF_ZEPHYR_HEAP_SIZE=0x60000
 CONFIG_VIRTUAL_HEAP=n
+
+# sof-ptl-nocodec.tplg requires more than 64 partitions for DP
+# (vregion is created for each pipeline)
+CONFIG_MAX_DOMAIN_PARTITIONS=128