diff --git a/arch/arm/src/lc823450/Make.defs b/arch/arm/src/lc823450/Make.defs
index 0519c2f123..6fbf42aef2 100644
--- a/arch/arm/src/lc823450/Make.defs
+++ b/arch/arm/src/lc823450/Make.defs
@@ -50,7 +50,7 @@ CMN_CSRCS += up_memfault.c up_modifyreg8.c up_modifyreg16.c up_modifyreg32.c
 CMN_CSRCS += up_releasepending.c up_releasestack.c up_reprioritizertr.c
 CMN_CSRCS += up_schedulesigaction.c up_sigdeliver.c up_systemreset.c
 CMN_CSRCS += up_unblocktask.c up_usestack.c up_doirq.c up_hardfault.c
-CMN_CSRCS += up_svcall.c up_vfork.c up_trigger_irq.c up_allocateheap.c
+CMN_CSRCS += up_svcall.c up_vfork.c up_trigger_irq.c
 
 # CMN_CSRCS += up_dwt.c
 
diff --git a/arch/arm/src/lc823450/lc823450_allocateheap2.c b/arch/arm/src/lc823450/lc823450_allocateheap2.c
index 02abdd4458..2cebe4ba0d 100644
--- a/arch/arm/src/lc823450/lc823450_allocateheap2.c
+++ b/arch/arm/src/lc823450/lc823450_allocateheap2.c
@@ -165,8 +165,8 @@ void up_allocate_heap(FAR void **heap_start, size_t *heap_size)
 
   /* Return the heap settings */
 
-  *heap_start = (FAR void *)g_idle_topstack;
-  *heap_size  = SRAM1_END - g_idle_topstack;
+  *heap_start = (uintptr_t *)&_eronly; /* please see ld.script */
+  *heap_size  = SRAM1_END - (int)heap_start;
 
   /* Colorize the heap for debug */