diff --git a/libraries/mbed/targets/cmsis/TARGET_WIZNET/TARGET_W7500x/TARGET_WIZwiki_W7500/TOOLCHAIN_ARM_MICRO/startup_W7500x.s b/libraries/mbed/targets/cmsis/TARGET_WIZNET/TARGET_W7500x/TARGET_WIZwiki_W7500/TOOLCHAIN_ARM_MICRO/startup_W7500x.s
index 410655e1f7..124a5e65c8 100644
--- a/libraries/mbed/targets/cmsis/TARGET_WIZNET/TARGET_W7500x/TARGET_WIZwiki_W7500/TOOLCHAIN_ARM_MICRO/startup_W7500x.s
+++ b/libraries/mbed/targets/cmsis/TARGET_WIZNET/TARGET_W7500x/TARGET_WIZwiki_W7500/TOOLCHAIN_ARM_MICRO/startup_W7500x.s
@@ -35,7 +35,7 @@ Stack_Size      EQU     0x00000400
 
                 AREA    STACK, NOINIT, READWRITE, ALIGN=3
 Stack_Mem       SPACE   Stack_Size
-__initial_sp    EQU     0x20004000 ; Top of RAM (8 KB for STM32F030R8)
+__initial_sp    EQU     0x20004000 ; Top of RAM (16 KB for WIZwiki_W7500)
 
 
 ; <h> Heap Configuration