diff --git a/targets/TARGET_NUVOTON/TARGET_M2354/TARGET_TFM/TARGET_NU_M2354/COMPONENT_TFM_S_FW/README.md b/targets/TARGET_NUVOTON/TARGET_M2354/TARGET_TFM/TARGET_NU_M2354/COMPONENT_TFM_S_FW/README.md
index 5b03c916e63..20196bcb4d5 100644
--- a/targets/TARGET_NUVOTON/TARGET_M2354/TARGET_TFM/TARGET_NU_M2354/COMPONENT_TFM_S_FW/README.md
+++ b/targets/TARGET_NUVOTON/TARGET_M2354/TARGET_TFM/TARGET_NU_M2354/COMPONENT_TFM_S_FW/README.md
@@ -136,6 +136,7 @@ Below summarize the copy paths from TF-M into Mbed:
 -   trusted-firmware-m/cmake_build/install/outputs/NUVOTON/M2354/tfm_s.bin → tfm_s.bin
 -   trusted-firmware-m/cmake_build/install/interface/lib/s_veneers.o → s_veneers.o
 -   trusted-firmware-m/platform/ext/target/nuvoton/m2354/partition/flash_layout.h → partition/flash_layout.h
+-   trusted-firmware-m/platform/ext/target/nuvoton/m2354/partition/partition_M2354.h → partition/partition_M2354_im.h
 -   trusted-firmware-m/platform/ext/target/nuvoton/m2354/partition/region_defs.h → partition/region_defs.h
 -   trusted-firmware-m/cmake_build/install/image_signing/layout_files/signing_layout_s.o → partition/signing_layout_s_preprocessed.h
 -   trusted-firmware-m/cmake_build/install/image_signing/layout_files/signing_layout_ns.o → partition/signing_layout_ns_preprocessed.h
diff --git a/targets/TARGET_NUVOTON/TARGET_M2354/TARGET_TFM/TARGET_NU_M2354/COMPONENT_TFM_S_FW/partition/flash_layout.h b/targets/TARGET_NUVOTON/TARGET_M2354/TARGET_TFM/TARGET_NU_M2354/COMPONENT_TFM_S_FW/partition/flash_layout.h
index 97561f51a97..582d855ee61 100644
--- a/targets/TARGET_NUVOTON/TARGET_M2354/TARGET_TFM/TARGET_NU_M2354/COMPONENT_TFM_S_FW/partition/flash_layout.h
+++ b/targets/TARGET_NUVOTON/TARGET_M2354/TARGET_TFM/TARGET_NU_M2354/COMPONENT_TFM_S_FW/partition/flash_layout.h
@@ -2,6 +2,8 @@
  * Copyright (c) 2017-2020 Arm Limited. All rights reserved.
  * Copyright (c) 2020 Nuvoton Technology Corp. All rights reserved.
  *
+ * SPDX-License-Identifier: Apache-2.0
+ *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
diff --git a/targets/TARGET_NUVOTON/TARGET_M2354/TARGET_TFM/TARGET_NU_M2354/COMPONENT_TFM_S_FW/partition/region_defs.h b/targets/TARGET_NUVOTON/TARGET_M2354/TARGET_TFM/TARGET_NU_M2354/COMPONENT_TFM_S_FW/partition/region_defs.h
index a1441a8dc22..704e73e7485 100644
--- a/targets/TARGET_NUVOTON/TARGET_M2354/TARGET_TFM/TARGET_NU_M2354/COMPONENT_TFM_S_FW/partition/region_defs.h
+++ b/targets/TARGET_NUVOTON/TARGET_M2354/TARGET_TFM/TARGET_NU_M2354/COMPONENT_TFM_S_FW/partition/region_defs.h
@@ -2,6 +2,8 @@
  * Copyright (c) 2017-2020 Arm Limited. All rights reserved.
  * Copyright (c) 2020 Nuvoton Technology Corp. All rights reserved.
  *
+ * SPDX-License-Identifier: Apache-2.0
+ *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
@@ -69,12 +71,35 @@
  * by the bootloader.
  */
 #ifdef BL2
-#define BL2_HEADER_SIZE      (0x400)       /* 1 KB */
-#define BL2_TRAILER_SIZE     (0x800)       /* 2 KB */
+#define BL2_HEADER_SIZE      (0x1000)       /* 4 KB */
+/* Evaluate image trailer size for 'SWAP' upgrade strategy
+ *
+ * Check the link below for necessary trailer size:
+ * https://www.mcuboot.com/documentation/design/
+ *
+ * With the formula:
+ * Swap status (BOOT_MAX_IMG_SECTORS * min-write-size * 3)
+ *
+ * Where for the platform:
+ * BOOT_MAX_IMG_SECTORS = 512 (= 1MiB / 2KiB)
+ * min-write-size = 4 bytes (per flash_area_align())
+ * Swap status = 512 * 4 * 3 = 6KiB
+ *
+ * 6KiB plus other fields for image trailer plus TLV, we reserve 8KiB in total.
+ *
+ * Notes for above estimation:
+ * 1. In image signing such as bl2/ext/mcuboot/CMakeLists.txt, `--align` must fix to 4 and `--max-sectors` must specify as 512 to catch trailer size overrun error.
+ * 2. 2KiB is taken from smaller of internal/external Flash's sector sizes.
+ * 3. Continuing above, SDH Flash's sector size should have adapted to larger from 512 bytes.
+ * 4. BL2_TRAILER_SIZE must include TLV area, though not mentioned.
+ * 5. For consistency, BL2_TRAILER_SIZE doesn't change across 'OVERWRITE_ONLY' and "SWAP" upgrade strategies.
+ * 6. For consistency, (BL2_HEADER_SIZE + BL2_TRAILER_SIZE) doesn't change across w/ and w/o BL2.
+ */
+#define BL2_TRAILER_SIZE     (0x2000)       /* 8 KB */
 #else
 /* No header if no bootloader, but keep IMAGE_CODE_SIZE the same */
 #define BL2_HEADER_SIZE      (0x0)
-#define BL2_TRAILER_SIZE     (0x800)
+#define BL2_TRAILER_SIZE     (0x3000)
 #endif /* BL2 */
 
 #define IMAGE_S_CODE_SIZE    (FLASH_S_PARTITION_SIZE - BL2_HEADER_SIZE - BL2_TRAILER_SIZE)
diff --git a/targets/TARGET_NUVOTON/TARGET_M2354/TARGET_TFM/TARGET_NU_M2354/COMPONENT_TFM_S_FW/s_veneers.o b/targets/TARGET_NUVOTON/TARGET_M2354/TARGET_TFM/TARGET_NU_M2354/COMPONENT_TFM_S_FW/s_veneers.o
index c963835056b..da13cd5e8fb 100644
Binary files a/targets/TARGET_NUVOTON/TARGET_M2354/TARGET_TFM/TARGET_NU_M2354/COMPONENT_TFM_S_FW/s_veneers.o and b/targets/TARGET_NUVOTON/TARGET_M2354/TARGET_TFM/TARGET_NU_M2354/COMPONENT_TFM_S_FW/s_veneers.o differ
diff --git a/targets/TARGET_NUVOTON/TARGET_M2354/TARGET_TFM/TARGET_NU_M2354/COMPONENT_TFM_S_FW/tfm_s.axf b/targets/TARGET_NUVOTON/TARGET_M2354/TARGET_TFM/TARGET_NU_M2354/COMPONENT_TFM_S_FW/tfm_s.axf
index c623aedfdb2..0b98be608fd 100644
Binary files a/targets/TARGET_NUVOTON/TARGET_M2354/TARGET_TFM/TARGET_NU_M2354/COMPONENT_TFM_S_FW/tfm_s.axf and b/targets/TARGET_NUVOTON/TARGET_M2354/TARGET_TFM/TARGET_NU_M2354/COMPONENT_TFM_S_FW/tfm_s.axf differ
diff --git a/targets/TARGET_NUVOTON/TARGET_M2354/TARGET_TFM/TARGET_NU_M2354/COMPONENT_TFM_S_FW/tfm_s.bin b/targets/TARGET_NUVOTON/TARGET_M2354/TARGET_TFM/TARGET_NU_M2354/COMPONENT_TFM_S_FW/tfm_s.bin
index 321ac85e755..9bdac860b6b 100644
Binary files a/targets/TARGET_NUVOTON/TARGET_M2354/TARGET_TFM/TARGET_NU_M2354/COMPONENT_TFM_S_FW/tfm_s.bin and b/targets/TARGET_NUVOTON/TARGET_M2354/TARGET_TFM/TARGET_NU_M2354/COMPONENT_TFM_S_FW/tfm_s.bin differ
diff --git a/targets/TARGET_NUVOTON/scripts/NUVOTON.py b/targets/TARGET_NUVOTON/scripts/NUVOTON.py
index e5b080671d1..5fd79845445 100644
--- a/targets/TARGET_NUVOTON/scripts/NUVOTON.py
+++ b/targets/TARGET_NUVOTON/scripts/NUVOTON.py
@@ -107,14 +107,14 @@ def tfm_sign_image(tfm_import_path, signing_key, signing_key_1, non_secure_bin):
         "--public-key-format",
         'full',
         "--align",
-        '1',
+        '4',
         # Reasons for removing padding and boot magic option "--pad":
         # 1. PSA FWU API psa_fwu_install() will be responsible for writing boot magic to enable upgradeable.
         # 2. The image size gets smaller instead of slot size.
         #"--pad",
         "--pad-header",
         "-H",
-        '0x400',
+        '0x1000',
         "--overwrite-only",
         "-s",
         'auto', # Or modified_timestamp