diff --git a/arch/arm/src/sama5/chip/sama5d3x_memorymap.h b/arch/arm/src/sama5/chip/sama5d3x_memorymap.h
index 310111fd798..288a60dcb51 100644
--- a/arch/arm/src/sama5/chip/sama5d3x_memorymap.h
+++ b/arch/arm/src/sama5/chip/sama5d3x_memorymap.h
@@ -616,8 +616,19 @@
 #    endif
 #    define PGTABLE_IN_HIGHSRAM   1
 
+  /* If we execute from SRAM but keep data in SDRAM, then we will also have
+   * to position the initial, IDLE stack in SRAM.  SDRAM will not be ready
+   * soon enough to serve as the stack.
+   *
+   * In this case, the initial IDLE stack can just follow the vector table,
+   * lying between the vector table and the page table.  We don't really
+   * know how much memory to set aside for the vector table, but 4KiB should
+   * be much more than enough
+   */
+
 #    ifdef CONFIG_BOOT_SDRAM_DATA
-#      error CONFIG_BOOT_SDRAM_DATA not suupported in this configuration
+#      define IDLE_STACK_PBASE    (SAM_ISRAM0_PADDR + 0x0001000)
+#      define IDLE_STACK_VBASE    (SAM_ISRAM0_VADDR + 0x0001000)
 #    endif
 
 #  else /* CONFIG_SAMA5_BOOT_ISRAM && CONFIG_ARCH_LOWVECTORS */
@@ -657,7 +668,13 @@
 #    error "One of PGTABLE_BASE_PADDR or PGTABLE_BASE_VADDR is undefined"
 #  endif
 
-  /* If data is in SDRAM, then the IDLE stack at the beginning of ISRAM */
+  /* If we execute from SRAM but keep data in SDRAM, then we will also have
+   * to position the initial, IDLE stack in SRAM.  SDRAM will not be ready
+   * soon enough to serve as the stack.
+   *
+   * In this case, the initial IDLE stack can just follow the page table
+   * in ISRAM.
+   */
 
 #    ifdef CONFIG_BOOT_SDRAM_DATA
 #      define IDLE_STACK_PBASE    (SAM_ISRAM0_PADDR + PGTABLE_SIZE)
diff --git a/arch/arm/src/sama5/chip/sama5d4x_memorymap.h b/arch/arm/src/sama5/chip/sama5d4x_memorymap.h
index 2643567f833..b40d953bcea 100644
--- a/arch/arm/src/sama5/chip/sama5d4x_memorymap.h
+++ b/arch/arm/src/sama5/chip/sama5d4x_memorymap.h
@@ -608,8 +608,19 @@
 #    endif
 #    define PGTABLE_IN_HIGHSRAM   1
 
+  /* If we execute from SRAM, but keep data in SDRAM, then we will also have
+   * to position the initial, IDLE stack in SRAM.  SDRAM will not be ready
+   * soon enough to serve as the stack.
+   *
+   * In this case, the initial IDLE stack can just follow the vector table,
+   * lying between the vector table and the page table.  We don't really
+   * know how much memory to set aside for the vector table, but 4KiB should
+   * be much more than enough
+   */
+
 #    ifdef CONFIG_BOOT_SDRAM_DATA
-#      error CONFIG_BOOT_SDRAM_DATA not suupported in this configuration
+#      define IDLE_STACK_PBASE    (SAM_ISRAM0_PADDR + 0x0001000)
+#      define IDLE_STACK_VBASE    (SAM_ISRAM0_VADDR + 0x0001000)
 #    endif
 
 #  else /* CONFIG_SAMA5_BOOT_ISRAM && CONFIG_ARCH_LOWVECTORS */
@@ -625,6 +636,14 @@
 #    endif
 #    define PGTABLE_IN_LOWSRAM    1
 
+  /* If we execute from SRAM, but keep data in SDRAM, then we will also have
+   * to position the initial, IDLE stack in SRAM.  SDRAM will not be ready
+   * soon enough to serve as the stack.
+   *
+   * In this case, the initial IDLE stack can just follow the page table
+   * in ISRAM.
+   */
+
 #    ifdef CONFIG_BOOT_SDRAM_DATA
 #      define IDLE_STACK_PBASE    (PGTABLE_BASE_PADDR + PGTABLE_SIZE)
 #      define IDLE_STACK_VBASE    (PGTABLE_BASE_VADDR + PGTABLE_SIZE)