diff --git a/.gitignore b/.gitignore
index 3139c130..75cc4046 100644
--- a/.gitignore
+++ b/.gitignore
@@ -133,6 +133,7 @@ tools/tpm/pcr_extend
 tools/tpm/policy_create
 tools/tpm/policy_sign
 config/*.ld
+config/*.sct
 test-lib
 lib-fs
 
diff --git a/Makefile b/Makefile
index dec0224b..4e2af07e 100644
--- a/Makefile
+++ b/Makefile
@@ -27,7 +27,8 @@ SIGN_ALG=
 OBJCOPY_FLAGS=
 BIG_ENDIAN?=0
 USE_CLANG?=0
-ifeq ($(USE_CLANG),1)
+USE_ARMCLANG?=0
+ifneq ($(filter 1,$(USE_CLANG) $(USE_ARMCLANG)),)
 USE_GCC?=0
 else
 USE_GCC?=1
@@ -251,6 +252,39 @@ ifeq ($(ARCH),AURIX_TC3)
   endif
 endif
 
+## ARM Compiler for Embedded (USE_ARMCLANG=1): rebuild the link options from
+## scratch and switch the linker script to a scatter file, to support armlink.
+ifeq ($(USE_ARMCLANG),1)
+  CFLAGS+=-D'END_STACK=Image$$$$ARM_LIB_STACK$$$$ZI$$$$Limit'
+  ifeq ($(WOLFCRYPT_TZ),1)
+    # Trap stubs for symbols referenced from wolfSSL code paths that are
+    # dead in this configuration: GNU ld garbage-collects the referencing
+    # sections, but armlink resolves all symbols before unused section
+    # elimination
+    OBJS+=tools/armclang/armclang_stubs.o
+    CFLAGS+=-DARMCLANG_STUBS_DEAD_REFS
+    ifeq ($(WOLFCRYPT_TZ_PKCS11),1)
+      CFLAGS+=-D'_flash_keyvault=Image$$$$KEYVAULT$$$$Base'
+      CFLAGS+=-D'_flash_keyvault_size=Image$$$$KEYVAULT$$$$ZI$$$$Length'
+      CFLAGS+=-D'_start_heap=Image$$$$RAM_HEAP$$$$Base'
+      CFLAGS+=-D'_heap_size=Image$$$$RAM_HEAP$$$$ZI$$$$Length'
+      # ARM libc malloc needs the C-library init that never runs (entry is
+      # isr_reset): provide a heap allocator instead
+      CFLAGS+=-DARMCLANG_STUBS_MALLOC
+    endif
+  endif
+  LDFLAGS:=$(ARMCLANG_LDFLAGS) --map --list=wolfboot.map
+  LSCRIPT:=config/target.sct
+  LSCRIPT_IN:=hal/$(TARGET).sct
+  LSCRIPT_FLAGS:=--scatter=$(LSCRIPT)
+  LD_START_GROUP:=
+  LD_END_GROUP:=
+  SECURE_LDFLAGS:=
+  ifeq ($(TZEN),1)
+    SECURE_LDFLAGS:=--import_cmse_lib_out=./src/wolfboot_tz_nsc.o
+  endif
+endif
+
 # Environment variables for sign tool
 SIGN_ENV=IMAGE_HEADER_SIZE=$(IMAGE_HEADER_SIZE) \
 		 WOLFBOOT_PARTITION_SIZE=$(WOLFBOOT_PARTITION_SIZE) \
@@ -656,7 +690,7 @@ src/flash_otp_keystore.o: $(PRIVATE_KEY) src/flash_otp_keystore.c
 keys: $(PRIVATE_KEY)
 
 clean:
-	$(Q)rm -f src/*.o hal/*.o hal/spi/*.o test-app/*.o src/x86/*.o
+	$(Q)rm -f src/*.o hal/*.o hal/spi/*.o hal/uart/*.o test-app/*.o src/x86/*.o
 	$(Q)rm -f src/wolfboot_tz_nsc.o
 	$(Q)rm -f $(WOLFBOOT_LIB_WOLFSSL)/wolfcrypt/src/*.o $(WOLFBOOT_LIB_WOLFTPM)/src/*.o $(WOLFBOOT_LIB_WOLFTPM)/src/fwtpm/*.o $(WOLFBOOT_LIB_WOLFTPM)/hal/*.o $(WOLFBOOT_LIB_WOLFTPM)/examples/pcr/*.o
 	$(Q)rm -f $(WOLFBOOT_LIB_WOLFSSL)/wolfcrypt/src/port/Renesas/*.o
diff --git a/arch.mk b/arch.mk
index f19e28c4..df8b0c80 100644
--- a/arch.mk
+++ b/arch.mk
@@ -1719,6 +1719,45 @@ ifeq ($(USE_CLANG),1)
   LDFLAGS+=-nostdlib
 endif
 
+ifeq ($(USE_ARMCLANG),1)
+  ifneq ($(ARCH),ARM)
+    $(error USE_ARMCLANG=1 is currently supported only for ARCH=ARM)
+  endif
+  ARMCLANG_PATH?=
+  CC=$(ARMCLANG_PATH)armclang --target=arm-arm-none-eabi
+  AS=$(CC)
+  LD=$(ARMCLANG_PATH)armlink
+  AR=$(ARMCLANG_PATH)armar
+  FROMELF?=$(ARMCLANG_PATH)fromelf
+  SIZE=$(FROMELF) -z
+  OBJCOPY=FROMELF="$(FROMELF)" $(WOLFBOOT_ROOT)/tools/armclang/objcopy.sh
+
+  CFLAGS+=-mfloat-abi=soft
+  CFLAGS+=-fno-unwind-tables -fno-asynchronous-unwind-tables
+  CFLAGS+=-Wno-unknown-attributes -Wno-error=unknown-attributes
+
+  # Map scatter files region names to GNU ld symbols used by wolfBoot code
+  CFLAGS+=-D'_start_text=Image$$$$ER_VECTORS$$$$Base'
+  CFLAGS+=-D'_stored_data=Load$$$$RW_RAM$$$$Base'
+  CFLAGS+=-D'_start_data=Image$$$$RW_RAM$$$$Base'
+  CFLAGS+=-D'_end_data=Image$$$$RW_RAM$$$$Limit'
+  CFLAGS+=-D'_start_bss=Image$$$$RW_RAM$$$$ZI$$$$Base'
+  CFLAGS+=-D'_end_bss=Image$$$$RW_RAM$$$$ZI$$$$Limit'
+
+  # Base armlink options shared by both images:
+  # - the unreferenced vector table needs an explicit --keep or unused
+  #   section elimination removes it
+  # - RW data compression must be off: wolfBoot copies .data to RAM itself,
+  #   word by word, and would copy the compressed image
+  # - Suppress L6314W (no section matches pattern) is suppressed: the scatter
+  #   files list sections that are only present in some configurations (e.g.
+  #   .ramcode)
+  # - --no_startup: wolfBoot has its own reset handler.
+  ARMCLANG_LDFLAGS=--cpu=Cortex-M33 --fpu=SoftVFP --entry=isr_reset \
+                   --keep="*(.isr_vector)" --datacompressor=off --remove \
+                   --no_startup --info=sizes,totals,unused --diag_suppress=6314
+endif
+
 ifeq ($(USE_GCC),1)
   ## Toolchain setup
   CC=$(CROSS_COMPILE)gcc
diff --git a/config/examples/stm32u5-wolfcrypt-tz.config b/config/examples/stm32u5-wolfcrypt-tz.config
index 5cd81fef..573be823 100644
--- a/config/examples/stm32u5-wolfcrypt-tz.config
+++ b/config/examples/stm32u5-wolfcrypt-tz.config
@@ -20,13 +20,13 @@ RAM_CODE?=0
 DUALBANK_SWAP?=0
 WOLFBOOT_PARTITION_SIZE?=0x20000
 WOLFBOOT_SECTOR_SIZE?=0x2000
-WOLFBOOT_KEYVAULT_ADDRESS?=0x0C020000
+WOLFBOOT_KEYVAULT_ADDRESS?=0x0C040000
 WOLFBOOT_KEYVAULT_SIZE?=0x18000
-WOLFBOOT_NSC_ADDRESS?=0x0C038000
+WOLFBOOT_NSC_ADDRESS?=0x0C058000
 WOLFBOOT_NSC_SIZE?=0x8000
-WOLFBOOT_PARTITION_BOOT_ADDRESS?=0x08040000
-WOLFBOOT_PARTITION_UPDATE_ADDRESS?=0x08060000
-WOLFBOOT_PARTITION_SWAP_ADDRESS?=0x08080000
+WOLFBOOT_PARTITION_BOOT_ADDRESS?=0x08060000
+WOLFBOOT_PARTITION_UPDATE_ADDRESS?=0x08080000
+WOLFBOOT_PARTITION_SWAP_ADDRESS?=0x080A0000
 FLAGS_HOME=0
 DISABLE_BACKUP=0
 WOLFCRYPT_TZ=1
diff --git a/docs/compile.md b/docs/compile.md
index 4f07f488..d7be8605 100644
--- a/docs/compile.md
+++ b/docs/compile.md
@@ -384,6 +384,25 @@ iterating over a range of flash sectors and erasing them one at a time. Setting
 single HAL flash erase invocation with a larger erase length versus the iterative approach. On targets where multi-sector erases are more performant, this option can be used to dramatically speed up the
 image swap procedure.
 
+### Building with the ARM Compiler for Embedded (armclang)
+
+wolfBoot can be built with the [ARM Compiler for Embedded](https://developer.arm.com/Tools%20and%20Software/Arm%20Compiler%20for%20Embedded)
+(AC6: `armclang`, `armlink`, `armar`, `fromelf`), the toolchain used by Keil
+MDK. No tool from the GNU or LLVM toolchains is required.
+
+At the moment, the only supported and tested target is the STM32U5
+(`config/examples/{stm32u5.config,stm32u5-wolfcrypt-tz.config}`).
+
+To use this, either have the AC6 tools in your `PATH` or set `ARMCLANG_PATH` to
+their location (including a trailing slash). Then build with USE_ARMCLANG=1:
+
+```
+cp config/examples/stm32u5.config .config
+make USE_ARMCLANG=1
+```
+
+Alternatively, append `USE_ARMCLANG=1` and/or `ARMCLANG_PATH` to your `.config`.
+
 ### Using Mac OS/X
 
 If you see 0xC3 0xBF (C3BF) repeated in your factory.bin then your OS is using Unicode characters.
diff --git a/hal/stm32u5.ld b/hal/stm32u5.ld
index 5f0da103..731053f2 100644
--- a/hal/stm32u5.ld
+++ b/hal/stm32u5.ld
@@ -1,6 +1,6 @@
 MEMORY
 {
-    FLASH (rx) :    ORIGIN = @WOLFBOOT_ORIGIN@, LENGTH = @WOLFBOOT_KEYVAULT_ADDRESS@ - @ARCH_FLASH_OFFSET@
+    FLASH (rx) :    ORIGIN = @WOLFBOOT_ORIGIN@, LENGTH = @WOLFBOOT_KEYVAULT_ADDRESS@ - @WOLFBOOT_ORIGIN@
     RAM (rwx) :     ORIGIN = 0x30000000, LENGTH = 0x00012000
     RAM_HEAP (rw):  ORIGIN = 0x30012000, LENGTH = 0xe000 /* 56KB Heap for wolfcrypt/PKCS11 */
     FLASH_KEYVAULT(rw): ORIGIN = @WOLFBOOT_KEYVAULT_ADDRESS@, LENGTH = @WOLFBOOT_KEYVAULT_SIZE@
diff --git a/hal/stm32u5.sct b/hal/stm32u5.sct
new file mode 100644
index 00000000..eb01fa70
--- /dev/null
+++ b/hal/stm32u5.sct
@@ -0,0 +1,64 @@
+#! armclang -E --target=arm-arm-none-eabi -mcpu=cortex-m33 -xc
+; wolfBoot stm32u5 (TZEN=1) scatter file for armlink, equivalent to
+; hal/stm32u5.ld. The @VAR@ placeholders are substituted by the Makefile
+; (same rule as the GNU linker scripts), then armlink runs the armclang
+; preprocessor on the result (#! line above).
+;
+; Region symbols consumed by the code (mapped from the GNU-ld symbol names
+; via -D in arch.mk / Makefile):
+;   ER_VECTORS      -> _start_text
+;   RW_RAM          -> _stored_data (load), _start_data/_end_data,
+;                      _start_bss/_end_bss
+;   ARM_LIB_STACK   -> END_STACK (stack top, grows down from end of RAM)
+;   RAM_HEAP        -> _start_heap/_heap_size (WOLFCRYPT_TZ PKCS11 heap)
+;   KEYVAULT        -> _flash_keyvault/_flash_keyvault_size
+
+#define WOLFBOOT_STACK_RESERVE 0x1000
+
+LR_FLASH @WOLFBOOT_ORIGIN@ (@WOLFBOOT_KEYVAULT_ADDRESS@ - @WOLFBOOT_ORIGIN@)
+{
+    ER_VECTORS @WOLFBOOT_ORIGIN@
+    {
+        *(.isr_vector, +FIRST)
+    }
+
+    ER_TEXT +0 ALIGN 8
+    {
+        .ANY(+RO)
+    }
+
+    RW_RAM 0x30000000 ALIGN 8 (0x00012000 - WOLFBOOT_STACK_RESERVE)
+    {
+        *(.ramcode)
+        .ANY(+RW)
+        .ANY(+ZI)
+    }
+
+    ; Empty region only used to define the initial stack pointer; also lets
+    ; armlink error out if RW_RAM grows into the stack reserve
+    ARM_LIB_STACK 0x30012000 EMPTY -WOLFBOOT_STACK_RESERVE
+    {
+    }
+
+#if @WOLFBOOT_KEYVAULT_SIZE@ + 0
+    ; 56KB heap for wolfcrypt/PKCS11
+    RAM_HEAP 0x30012000 EMPTY 0xe000
+    {
+    }
+
+    KEYVAULT @WOLFBOOT_KEYVAULT_ADDRESS@ EMPTY @WOLFBOOT_KEYVAULT_SIZE@
+    {
+    }
+#endif
+}
+
+; CMSE secure gateway veneers, generated by armlink. Placed at NSC + 0x400
+; like the GNU script (hal/stm32u5.ld reserves the first 0x400 bytes of the
+; NSC region).
+LR_NSC (@WOLFBOOT_NSC_ADDRESS@ + 0x400) (@WOLFBOOT_NSC_SIZE@ - 0x400)
+{
+    ER_NSC (@WOLFBOOT_NSC_ADDRESS@ + 0x400)
+    {
+        *(Veneer$$CMSE)
+    }
+}
diff --git a/options.mk b/options.mk
index 6f9b9ae4..a463d67e 100644
--- a/options.mk
+++ b/options.mk
@@ -39,7 +39,8 @@ WOLFHSM_SERVER_OBJS := \
   $(WOLFBOOT_LIB_WOLFHSM)/src/wh_message_comm.o
 
 USE_CLANG?=0
-ifeq ($(USE_CLANG),1)
+USE_ARMCLANG?=0
+ifneq ($(filter 1,$(USE_CLANG) $(USE_ARMCLANG)),)
   USE_GCC?=0
 else
   USE_GCC?=1
@@ -56,6 +57,18 @@ ifeq ($(USE_CLANG),1)
   endif
 endif
 
+ifeq ($(USE_ARMCLANG),1)
+  ifeq ($(USE_GCC),1)
+    $(error USE_ARMCLANG=1 is incompatible with USE_GCC=1; set USE_GCC=0)
+  endif
+  ifeq ($(USE_CLANG),1)
+    $(error USE_ARMCLANG=1 is incompatible with USE_CLANG=1)
+  endif
+  ifeq ($(ARMORED),1)
+    $(error USE_ARMCLANG=1 requires ARMORED=0)
+  endif
+endif
+
 # Support for Built-in ROT into OTP flash memory
 ifeq ($(FLASH_OTP_KEYSTORE),1)
     CFLAGS+=-D"FLASH_OTP_KEYSTORE"
diff --git a/test-app/ARM-stm32u5-ns.sct b/test-app/ARM-stm32u5-ns.sct
new file mode 100644
index 00000000..f714bb88
--- /dev/null
+++ b/test-app/ARM-stm32u5-ns.sct
@@ -0,0 +1,40 @@
+#! armclang -E --target=arm-arm-none-eabi -mcpu=cortex-m33 -xc
+; wolfBoot test-app stm32u5 (TZEN=1, non-secure app) scatter file for
+; armlink, equivalent to test-app/ARM-stm32u5-ns.ld.
+;
+; Region symbols (mapped from the GNU-ld symbol names via -D in arch.mk and
+; test-app/Makefile):
+;   ER_VECTORS      -> _start_text
+;   RW_RAM          -> _stored_data (load), _start_data/_end_data,
+;                      _start_bss/_end_bss, _start_heap (= end of ZI)
+;   ARM_LIB_STACK   -> _end_stack (stack top, grows down from end of RAM)
+
+#define APP_RAM_BASE 0x20020000
+#define APP_RAM_SIZE 0x00020000
+#define APP_STACK_RESERVE 0x1000
+
+LR_FLASH @WOLFBOOT_TEST_APP_ADDRESS@ @WOLFBOOT_TEST_APP_SIZE@
+{
+    ER_VECTORS @WOLFBOOT_TEST_APP_ADDRESS@
+    {
+        *(.isr_vector, +FIRST)
+    }
+
+    ER_TEXT +0 ALIGN 8
+    {
+        .ANY(+RO)
+    }
+
+    RW_RAM APP_RAM_BASE ALIGN 8 (APP_RAM_SIZE - APP_STACK_RESERVE)
+    {
+        *(.ramcode)
+        .ANY(+RW)
+        .ANY(+ZI)
+    }
+
+    ; Empty region only used to define the initial stack pointer; also lets
+    ; armlink error out if RW_RAM grows into the stack reserve
+    ARM_LIB_STACK (APP_RAM_BASE + APP_RAM_SIZE) EMPTY -APP_STACK_RESERVE
+    {
+    }
+}
diff --git a/test-app/Makefile b/test-app/Makefile
index f8058a34..bb27fd6b 100644
--- a/test-app/Makefile
+++ b/test-app/Makefile
@@ -1258,6 +1258,19 @@ ifeq ($(PPC64),1)
   CFLAGS:=$(filter-out -DWOLFSSL_PPC32_ASM -DWOLFSSL_PPC32_ASM_INLINE,$(CFLAGS))
 endif
 
+## ARM Compiler for Embedded (USE_ARMCLANG=1): rebuild the link options from
+## scratch, since the GNU-specific LDFLAGS accumulated above don't apply to
+## armlink, and switch the linker script to a scatter file.
+ifeq ($(USE_ARMCLANG),1)
+  CFLAGS+=-D'_end_stack=Image$$$$ARM_LIB_STACK$$$$ZI$$$$Limit'
+  CFLAGS+=-D'_start_heap=Image$$$$RW_RAM$$$$ZI$$$$Limit'
+  # GCC-only flags accumulated above
+  CFLAGS:=$(filter-out -Wstack-usage=% -gstabs,$(CFLAGS))
+  LSCRIPT:=../config/target-app.sct
+  LSCRIPT_TEMPLATE:=ARM-$(TARGET)-ns.sct
+  LDFLAGS:=$(ARMCLANG_LDFLAGS) --map --list=image.map --scatter=$(LSCRIPT)
+endif
+
 # Capture final flags for locally built wolfSSL objects.
 WOLFSSL_CFLAGS:=$(CFLAGS)
 WOLFTPM_CFLAGS:=$(CFLAGS)
diff --git a/test-app/wcs/user_settings.h b/test-app/wcs/user_settings.h
index b09accff..095b748b 100644
--- a/test-app/wcs/user_settings.h
+++ b/test-app/wcs/user_settings.h
@@ -27,7 +27,8 @@
 
 #include <target.h>
 #include <time.h>
-int clock_gettime (clockid_t clock_id, struct timespec *tp);
+struct timespec;
+int clock_gettime (unsigned long clock_id, struct timespec *tp);
 #include "wolfboot/wc_secure.h"
 
 #define WOLFCRYPT_ONLY
diff --git a/tools/armclang/armclang_stubs.c b/tools/armclang/armclang_stubs.c
new file mode 100644
index 00000000..d561637c
--- /dev/null
+++ b/tools/armclang/armclang_stubs.c
@@ -0,0 +1,182 @@
+/* armclang_stubs.c
+ *
+ * C library glue for building wolfBoot with the ARM Compiler for Embedded
+ * (USE_ARMCLANG=1). Only used by the WOLFCRYPT_TZ/PKCS11 configurations.
+ *
+ * - ARMCLANG_STUBS_MALLOC (secure image): heap allocator over the RAM_HEAP
+ *   scatter region. The GNU build uses newlib-nano's malloc on top of the
+ *   _sbrk hook in src/pkcs11_store.c; the ARM C library malloc cannot be
+ *   used instead because it requires the C library runtime initialization
+ *   (__rt_entry), which never runs since wolfBoot enters at isr_reset.
+ *
+ * - ARMCLANG_STUBS_DEAD_REFS: trap stubs for symbols that are only
+ *   referenced from sections that GNU ld garbage-collects; armlink needs
+ *   the definitions to exist before its own unused section elimination.
+ *
+ * This file is part of wolfBoot.
+ *
+ * wolfBoot is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * wolfBoot is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#ifdef ARMCLANG_STUBS_MALLOC
+
+#include <stddef.h>
+#include <stdint.h>
+#include <string.h>
+
+/* Renamed to the RAM_HEAP region symbols by the -D options in the Makefile */
+extern unsigned int _start_heap;
+extern unsigned int _heap_size;
+
+/* First-fit allocator with address-ordered free list and coalescing.
+ * Block header keeps the total block size (header included); blocks and
+ * payloads are 8-byte aligned. */
+struct heap_blk {
+    size_t size;
+    struct heap_blk *next;
+};
+
+#define HEAP_ALIGN(sz) (((sz) + 7U) & ~(size_t)7U)
+#define HEAP_MIN_SPLIT (sizeof(struct heap_blk) + 8U)
+
+static struct heap_blk *heap_free_list;
+static int heap_initialized;
+
+static void heap_init(void)
+{
+    heap_free_list = (struct heap_blk *)HEAP_ALIGN((uintptr_t)&_start_heap);
+    heap_free_list->size = (size_t)((uintptr_t)&_start_heap
+            + (uintptr_t)&_heap_size - (uintptr_t)heap_free_list)
+            & ~(size_t)7U;
+    heap_free_list->next = NULL;
+    heap_initialized = 1;
+}
+
+void *malloc(size_t size)
+{
+    struct heap_blk *blk, **prev;
+
+    if (!heap_initialized)
+        heap_init();
+    if (size == 0)
+        return NULL;
+    size = HEAP_ALIGN(size) + sizeof(struct heap_blk);
+
+    for (prev = &heap_free_list; (blk = *prev) != NULL; prev = &blk->next) {
+        if (blk->size < size)
+            continue;
+        if (blk->size - size >= HEAP_MIN_SPLIT) {
+            struct heap_blk *rest = (struct heap_blk *)((uint8_t *)blk + size);
+            rest->size = blk->size - size;
+            rest->next = blk->next;
+            blk->size = size;
+            *prev = rest;
+        } else {
+            *prev = blk->next;
+        }
+        blk->next = NULL;
+        return (uint8_t *)blk + sizeof(struct heap_blk);
+    }
+    return NULL;
+}
+
+void free(void *ptr)
+{
+    struct heap_blk *blk, *cur, **prev;
+
+    if (ptr == NULL)
+        return;
+    blk = (struct heap_blk *)((uint8_t *)ptr - sizeof(struct heap_blk));
+
+    /* Keep the free list sorted by address */
+    for (prev = &heap_free_list; (cur = *prev) != NULL; prev = &cur->next) {
+        if (cur > blk)
+            break;
+    }
+    blk->next = cur;
+    *prev = blk;
+
+    /* Coalesce with the next and previous blocks when adjacent */
+    if (cur != NULL && (uint8_t *)blk + blk->size == (uint8_t *)cur) {
+        blk->size += cur->size;
+        blk->next = cur->next;
+    }
+    if (prev != &heap_free_list) {
+        struct heap_blk *before = (struct heap_blk *)((uint8_t *)prev
+                - offsetof(struct heap_blk, next));
+        if ((uint8_t *)before + before->size == (uint8_t *)blk) {
+            before->size += blk->size;
+            before->next = blk->next;
+        }
+    }
+}
+
+void *calloc(size_t nmemb, size_t size)
+{
+    void *ptr;
+    size_t total = nmemb * size;
+
+    if (size != 0 && total / size != nmemb)
+        return NULL;
+    ptr = malloc(total);
+    if (ptr != NULL)
+        memset(ptr, 0, total);
+    return ptr;
+}
+
+void *realloc(void *ptr, size_t size)
+{
+    void *new_ptr;
+    struct heap_blk *blk;
+    size_t old_payload;
+
+    if (ptr == NULL)
+        return malloc(size);
+    if (size == 0) {
+        free(ptr);
+        return NULL;
+    }
+    blk = (struct heap_blk *)((uint8_t *)ptr - sizeof(struct heap_blk));
+    old_payload = blk->size - sizeof(struct heap_blk);
+    if (old_payload >= size)
+        return ptr;
+    new_ptr = malloc(size);
+    if (new_ptr != NULL) {
+        memcpy(new_ptr, ptr, old_payload);
+        free(ptr);
+    }
+    return new_ptr;
+}
+
+#endif /* ARMCLANG_STUBS_MALLOC */
+
+#ifdef ARMCLANG_STUBS_DEAD_REFS
+
+/* Trap stubs for symbols that are referenced only from wolfSSL sections
+ * that are dead in the wolfBoot configurations (proven by the GNU builds,
+ * where the references would be a link error if the referencing sections
+ * survived garbage collection). armlink resolves all symbols before its
+ * unused section elimination, so the references need a definition; both
+ * the stubs and the referencing sections are eliminated from the image.
+ * The infinite loop makes any unexpected live call fail loudly. */
+
+#define ARMCLANG_DEAD_REF_STUB(name) \
+    void name(void); \
+    void name(void) { while (1) ; }
+
+ARMCLANG_DEAD_REF_STUB(wc_CryptKey)
+ARMCLANG_DEAD_REF_STUB(Base64_Encode)
+ARMCLANG_DEAD_REF_STUB(wc_PKCS12_PBKDF)
+
+#endif /* ARMCLANG_STUBS_DEAD_REFS */
diff --git a/tools/armclang/objcopy.sh b/tools/armclang/objcopy.sh
new file mode 100755
index 00000000..b9f94525
--- /dev/null
+++ b/tools/armclang/objcopy.sh
@@ -0,0 +1,80 @@
+#!/bin/sh
+# GNU objcopy command-line adapter over ARM fromelf, used when building with
+# the ARM Compiler for Embedded (USE_ARMCLANG=1) so that the .bin/.hex/.srec
+# Makefile recipes can be shared with the GNU toolchains.
+#
+# Only the invocation shapes used by the wolfBoot Makefiles are supported:
+#   objcopy [--gap-fill <byte>] -O binary <in.elf> <out.bin>
+#   objcopy -O ihex <in.elf> <out.hex>
+#   objcopy -O srec <in.elf> <out.srec>
+#
+# The fromelf executable is taken from the FROMELF environment variable
+# (default: fromelf).
+
+set -e
+
+FROMELF="${FROMELF:-fromelf}"
+GAP_FILL=
+FORMAT=
+INPUT=
+OUTPUT=
+
+while [ $# -gt 0 ]; do
+    case "$1" in
+        --gap-fill)
+            GAP_FILL="$2"
+            shift 2
+            ;;
+        --gap-fill=*)
+            GAP_FILL="${1#*=}"
+            shift
+            ;;
+        -O)
+            FORMAT="$2"
+            shift 2
+            ;;
+        -*)
+            echo "$0: unsupported objcopy option: $1" >&2
+            exit 1
+            ;;
+        *)
+            if [ -z "$INPUT" ]; then
+                INPUT="$1"
+            elif [ -z "$OUTPUT" ]; then
+                OUTPUT="$1"
+            else
+                echo "$0: too many arguments: $1" >&2
+                exit 1
+            fi
+            shift
+            ;;
+    esac
+done
+
+if [ -z "$FORMAT" ] || [ -z "$INPUT" ] || [ -z "$OUTPUT" ]; then
+    echo "usage: $0 [--gap-fill <byte>] -O binary|ihex|srec <in.elf> <out>" >&2
+    exit 1
+fi
+
+case "$FORMAT" in
+    binary)
+        # --bincombined merges all load regions into a single image, padding
+        # the gaps between them (GNU objcopy -O binary behavior)
+        set -- --bincombined
+        if [ -n "$GAP_FILL" ]; then
+            set -- "$@" "--bincombined_padding=1,$GAP_FILL"
+        fi
+        ;;
+    ihex)
+        set -- --i32combined
+        ;;
+    srec)
+        set -- --m32combined
+        ;;
+    *)
+        echo "$0: unsupported output format: $FORMAT" >&2
+        exit 1
+        ;;
+esac
+
+exec "$FROMELF" "$@" --output="$OUTPUT" "$INPUT"