diff --git a/core/embed/boardloader/startup_stm32u5.s b/core/embed/boardloader/startup_stm32u5.s
index fc30e4b63..3665db2de 100644
--- a/core/embed/boardloader/startup_stm32u5.s
+++ b/core/embed/boardloader/startup_stm32u5.s
@@ -7,7 +7,7 @@
 reset_handler:
   // set the stack protection
   ldr r0, =_sstack
-  add r0, r0, #16        // padding
+  add r0, r0, #128      // safety margin for the exception frame
   msr MSPLIM, r0
 
   bl SystemInit
diff --git a/core/embed/bootloader/startup_stm32u5.s b/core/embed/bootloader/startup_stm32u5.s
index 0f90b0108..6f5c36e73 100644
--- a/core/embed/bootloader/startup_stm32u5.s
+++ b/core/embed/bootloader/startup_stm32u5.s
@@ -7,7 +7,7 @@
 reset_handler:
   // set the stack protection
   ldr r0, =_sstack
-  add r0, r0, #16        // padding
+  add r0, r0, #128       // safety margin for the exception frame
   msr MSPLIM, r0
 
   // setup environment for subsequent stage of code
diff --git a/core/embed/bootloader_ci/startup_stm32u5.s b/core/embed/bootloader_ci/startup_stm32u5.s
index ab5b61495..707b7a320 100644
--- a/core/embed/bootloader_ci/startup_stm32u5.s
+++ b/core/embed/bootloader_ci/startup_stm32u5.s
@@ -7,7 +7,7 @@
 reset_handler:
   // set the stack protection
   ldr r0, =_sstack
-  add r0, r0, #16        // padding
+  add r0, r0, #128       // safety margin for the exception frame
   msr MSPLIM, r0
 
   // setup environment for subsequent stage of code
diff --git a/core/embed/firmware/startup_stm32u5.S b/core/embed/firmware/startup_stm32u5.S
index f37f5b092..db9a204c3 100644
--- a/core/embed/firmware/startup_stm32u5.S
+++ b/core/embed/firmware/startup_stm32u5.S
@@ -7,7 +7,7 @@
 reset_handler:
   // set the stack protection
   ldr r0, =_sstack
-  add r0, r0, #16        // padding
+  add r0, r0, #128       // safety margin for the exception frame
   msr MSPLIM, r0
 
   // setup environment for subsequent stage of code
diff --git a/core/embed/prodtest/startup_stm32u5.s b/core/embed/prodtest/startup_stm32u5.s
index f37f5b092..db9a204c3 100644
--- a/core/embed/prodtest/startup_stm32u5.s
+++ b/core/embed/prodtest/startup_stm32u5.s
@@ -7,7 +7,7 @@
 reset_handler:
   // set the stack protection
   ldr r0, =_sstack
-  add r0, r0, #16        // padding
+  add r0, r0, #128       // safety margin for the exception frame
   msr MSPLIM, r0
 
   // setup environment for subsequent stage of code
diff --git a/core/embed/reflash/startup_stm32u5.s b/core/embed/reflash/startup_stm32u5.s
index f37f5b092..db9a204c3 100644
--- a/core/embed/reflash/startup_stm32u5.s
+++ b/core/embed/reflash/startup_stm32u5.s
@@ -7,7 +7,7 @@
 reset_handler:
   // set the stack protection
   ldr r0, =_sstack
-  add r0, r0, #16        // padding
+  add r0, r0, #128       // safety margin for the exception frame
   msr MSPLIM, r0
 
   // setup environment for subsequent stage of code