diff --git a/Device/ARMCM23/Source/startup_ARMCM23.c b/Device/ARMCM23/Source/startup_ARMCM23.c
index c36a9ab..893a4ed 100644
--- a/Device/ARMCM23/Source/startup_ARMCM23.c
+++ b/Device/ARMCM23/Source/startup_ARMCM23.c
@@ -34,7 +34,7 @@
 extern uint32_t __INITIAL_SP;
 extern uint32_t __STACK_LIMIT;
 #if defined (__ARM_FEATURE_CMSE) && (__ARM_FEATURE_CMSE == 3U)
-extern uint32_t __STACK_SEAL;
+extern uint64_t __STACK_SEAL;
 #endif
 
 extern __NO_RETURN void __PROGRAM_START(void);
diff --git a/Device/ARMCM33/Source/startup_ARMCM33.c b/Device/ARMCM33/Source/startup_ARMCM33.c
index a9432a1..bd415ca 100644
--- a/Device/ARMCM33/Source/startup_ARMCM33.c
+++ b/Device/ARMCM33/Source/startup_ARMCM33.c
@@ -34,7 +34,7 @@
 extern uint32_t __INITIAL_SP;
 extern uint32_t __STACK_LIMIT;
 #if defined (__ARM_FEATURE_CMSE) && (__ARM_FEATURE_CMSE == 3U)
-extern uint32_t __STACK_SEAL;
+extern uint64_t __STACK_SEAL;
 #endif
 
 extern __NO_RETURN void __PROGRAM_START(void);
diff --git a/Device/ARMCM35P/Source/startup_ARMCM35P.c b/Device/ARMCM35P/Source/startup_ARMCM35P.c
index f04f9ff..26c23bd 100644
--- a/Device/ARMCM35P/Source/startup_ARMCM35P.c
+++ b/Device/ARMCM35P/Source/startup_ARMCM35P.c
@@ -34,7 +34,7 @@
 extern uint32_t __INITIAL_SP;
 extern uint32_t __STACK_LIMIT;
 #if defined (__ARM_FEATURE_CMSE) && (__ARM_FEATURE_CMSE == 3U)
-extern uint32_t __STACK_SEAL;
+extern uint64_t __STACK_SEAL;
 #endif
 
 extern __NO_RETURN void __PROGRAM_START(void);
diff --git a/Device/ARMCM52/Source/startup_ARMCM52.c b/Device/ARMCM52/Source/startup_ARMCM52.c
index e13ce26..0875f3c 100644
--- a/Device/ARMCM52/Source/startup_ARMCM52.c
+++ b/Device/ARMCM52/Source/startup_ARMCM52.c
@@ -34,7 +34,7 @@
 extern uint32_t __INITIAL_SP;
 extern uint32_t __STACK_LIMIT;
 #if defined (__ARM_FEATURE_CMSE) && (__ARM_FEATURE_CMSE == 3U)
-extern uint32_t __STACK_SEAL;
+extern uint64_t __STACK_SEAL;
 #endif
 
 extern __NO_RETURN void __PROGRAM_START(void);
diff --git a/Device/ARMCM55/Source/startup_ARMCM55.c b/Device/ARMCM55/Source/startup_ARMCM55.c
index 0557c5f..d0a244b 100644
--- a/Device/ARMCM55/Source/startup_ARMCM55.c
+++ b/Device/ARMCM55/Source/startup_ARMCM55.c
@@ -34,7 +34,7 @@
 extern uint32_t __INITIAL_SP;
 extern uint32_t __STACK_LIMIT;
 #if defined (__ARM_FEATURE_CMSE) && (__ARM_FEATURE_CMSE == 3U)
-extern uint32_t __STACK_SEAL;
+extern uint64_t __STACK_SEAL;
 #endif
 
 extern __NO_RETURN void __PROGRAM_START(void);
diff --git a/Device/ARMCM85/Source/startup_ARMCM85.c b/Device/ARMCM85/Source/startup_ARMCM85.c
index 067871d..b04cdf8 100644
--- a/Device/ARMCM85/Source/startup_ARMCM85.c
+++ b/Device/ARMCM85/Source/startup_ARMCM85.c
@@ -34,7 +34,7 @@
 extern uint32_t __INITIAL_SP;
 extern uint32_t __STACK_LIMIT;
 #if defined (__ARM_FEATURE_CMSE) && (__ARM_FEATURE_CMSE == 3U)
-extern uint32_t __STACK_SEAL;
+extern uint64_t __STACK_SEAL;
 #endif
 
 extern __NO_RETURN void __PROGRAM_START(void);