diff --git a/cmsis/CMSIS_5/CMSIS/RTOS2/RTX/CMakeLists.txt b/cmsis/CMSIS_5/CMSIS/RTOS2/RTX/CMakeLists.txt
index 3695d5bd1e2..e25cbf8067f 100644
--- a/cmsis/CMSIS_5/CMSIS/RTOS2/RTX/CMakeLists.txt
+++ b/cmsis/CMSIS_5/CMSIS/RTOS2/RTX/CMakeLists.txt
@@ -39,11 +39,7 @@ if(${CMAKE_CROSSCOMPILING})
     
     _mbed_get_cortex_a_exception_handlers()
     
-    if(${MBED_TOOLCHAIN} STREQUAL "GCC_ARM")
-        _mbed_get_cortex_m_exception_handlers(TOOLCHAIN_GCC)
-    elseif(${MBED_TOOLCHAIN} STREQUAL "ARM")
-        _mbed_get_cortex_m_exception_handlers(TOOLCHAIN_ARM)
-    endif()
+    _mbed_get_cortex_m_exception_handlers(TOOLCHAIN_GCC)
 endif()
 
 target_include_directories(mbed-rtos
diff --git a/cmsis/CMSIS_5/CMSIS/RTOS2/RTX/Source/TOOLCHAIN_GCC/TARGET_M0/irq_cm0.S b/cmsis/CMSIS_5/CMSIS/RTOS2/RTX/Source/TOOLCHAIN_GCC/TARGET_M0/irq_cm0.S
index e261cd066fe..4d1359116e6 100644
--- a/cmsis/CMSIS_5/CMSIS/RTOS2/RTX/Source/TOOLCHAIN_GCC/TARGET_M0/irq_cm0.S
+++ b/cmsis/CMSIS_5/CMSIS/RTOS2/RTX/Source/TOOLCHAIN_GCC/TARGET_M0/irq_cm0.S
@@ -102,7 +102,7 @@ SVC_ContextRestore:
         SUBS     R0,R0,#32              // Adjust address
         LDMIA    R0!,{R4-R7}            // Restore R4..R7
 
-        MOVS     R0,#~0xFFFFFFFD
+        MOVS     R0,#2                  // Binary complement of 0xFFFFFFFD
         MVNS     R0,R0                  // Set EXC_RETURN value
         BX       R0                     // Exit from handler
 
diff --git a/cmsis/CMSIS_5/CMSIS/RTOS2/RTX/Source/TOOLCHAIN_GCC/TARGET_M0P/irq_cm0.S b/cmsis/CMSIS_5/CMSIS/RTOS2/RTX/Source/TOOLCHAIN_GCC/TARGET_M0P/irq_cm0.S
index e261cd066fe..4d1359116e6 100644
--- a/cmsis/CMSIS_5/CMSIS/RTOS2/RTX/Source/TOOLCHAIN_GCC/TARGET_M0P/irq_cm0.S
+++ b/cmsis/CMSIS_5/CMSIS/RTOS2/RTX/Source/TOOLCHAIN_GCC/TARGET_M0P/irq_cm0.S
@@ -102,7 +102,7 @@ SVC_ContextRestore:
         SUBS     R0,R0,#32              // Adjust address
         LDMIA    R0!,{R4-R7}            // Restore R4..R7
 
-        MOVS     R0,#~0xFFFFFFFD
+        MOVS     R0,#2                  // Binary complement of 0xFFFFFFFD
         MVNS     R0,R0                  // Set EXC_RETURN value
         BX       R0                     // Exit from handler
 
diff --git a/platform/source/TARGET_CORTEX_M/CMakeLists.txt b/platform/source/TARGET_CORTEX_M/CMakeLists.txt
index 481d09bd215..298fa20a28b 100644
--- a/platform/source/TARGET_CORTEX_M/CMakeLists.txt
+++ b/platform/source/TARGET_CORTEX_M/CMakeLists.txt
@@ -1,11 +1,7 @@
 # Copyright (c) 2020-2021 ARM Limited. All rights reserved.
 # SPDX-License-Identifier: Apache-2.0
 
-if(${MBED_TOOLCHAIN} STREQUAL "GCC_ARM")
-    target_sources(mbed-core INTERFACE TOOLCHAIN_GCC/except.S)
-elseif(${MBED_TOOLCHAIN} STREQUAL "ARM")
-    target_sources(mbed-core INTERFACE TOOLCHAIN_ARM/except.S)
-endif()
+target_sources(mbed-core INTERFACE TOOLCHAIN_GCC/except.S)
 
 target_sources(mbed-core
     INTERFACE
diff --git a/platform/source/TARGET_CORTEX_M/TOOLCHAIN_GCC/except.S b/platform/source/TARGET_CORTEX_M/TOOLCHAIN_GCC/except.S
index a40e743cf1e..ac95155fd4a 100644
--- a/platform/source/TARGET_CORTEX_M/TOOLCHAIN_GCC/except.S
+++ b/platform/source/TARGET_CORTEX_M/TOOLCHAIN_GCC/except.S
@@ -105,7 +105,11 @@ UsageFault_Handler:
 Fault_Handler:
 #if (DOMAIN_NS == 1)
 #if MBED_CONF_PLATFORM_CRASH_CAPTURE_ENABLED
+#if defined(__ARMCC_VERSION)
+#define mbed_fault_context Image$$RW_m_crash_data$$ZI$$Base
+#else
 #define mbed_fault_context __CRASH_DATA_RAM_START__
+#endif
 #endif
 
         MOV     R12,R3
diff --git a/tools/cmake/cores/Cortex-M55.cmake b/tools/cmake/cores/Cortex-M55.cmake
index 796ee4823dc..37410aa9f39 100644
--- a/tools/cmake/cores/Cortex-M55.cmake
+++ b/tools/cmake/cores/Cortex-M55.cmake
@@ -17,13 +17,6 @@ elseif(${MBED_TOOLCHAIN} STREQUAL "ARM")
     )
 endif()
 
-# We'd like to use just "-mcpu=cortex-m55" in common_options, but due to a bug
-# in armclang passing options to armasm, we use the following flags as a
-# workaround to select M55.
-list(APPEND asm_compile_options
-    -mcpu=cortex-r7
-    -Wa,--cpu=cortex-m55
-)
 
 function(mbed_set_cpu_core_definitions target)
     target_compile_definitions(${target}