diff --git a/cmsis/CMSIS_5/CMSIS/RTOS2/RTX/CMakeLists.txt b/cmsis/CMSIS_5/CMSIS/RTOS2/RTX/CMakeLists.txt
index 2a3d39f..e742f14 100644
--- a/cmsis/CMSIS_5/CMSIS/RTOS2/RTX/CMakeLists.txt
+++ b/cmsis/CMSIS_5/CMSIS/RTOS2/RTX/CMakeLists.txt
@@ -1,4 +1,4 @@
-# Copyright (c) 2020 ARM Limited. All rights reserved.
+# Copyright (c) 2020-2021 ARM Limited. All rights reserved.
 # SPDX-License-Identifier: Apache-2.0
 
 function(_mbed_get_cortex_m_exception_handlers toolchain_dir)
@@ -42,8 +42,6 @@
     _mbed_get_cortex_m_exception_handlers(TOOLCHAIN_GCC)
 elseif(${MBED_TOOLCHAIN} STREQUAL "ARM")
     _mbed_get_cortex_m_exception_handlers(TOOLCHAIN_ARM)
-elseif(${MBED_TOOLCHAIN} STREQUAL "IAR")
-    _mbed_get_cortex_m_exception_handlers(TOOLCHAIN_IAR)
 endif()
 
 target_include_directories(mbed-rtos
diff --git a/cmsis/device/rtos/CMakeLists.txt b/cmsis/device/rtos/CMakeLists.txt
index 27e0c37..024cf56 100644
--- a/cmsis/device/rtos/CMakeLists.txt
+++ b/cmsis/device/rtos/CMakeLists.txt
@@ -1,4 +1,4 @@
-# Copyright (c) 2020 ARM Limited. All rights reserved.
+# Copyright (c) 2020-2021 ARM Limited. All rights reserved.
 # SPDX-License-Identifier: Apache-2.0
 
 if(${MBED_TOOLCHAIN} STREQUAL "GCC_ARM")
@@ -11,11 +11,6 @@
         INTERFACE
             TOOLCHAIN_ARM_STD/mbed_boot_arm_std.c
     )
-elseif(${MBED_TOOLCHAIN} STREQUAL "IAR")
-    target_sources(mbed-rtos
-        INTERFACE
-            TOOLCHAIN_IAR/mbed_boot_iar.c
-    )
 endif()
 
 target_include_directories(mbed-rtos
diff --git a/connectivity/drivers/emac/TARGET_RDA_EMAC/lwip-wifi/arch/TARGET_RDA/TARGET_UNO_91H/lib/CMakeLists.txt b/connectivity/drivers/emac/TARGET_RDA_EMAC/lwip-wifi/arch/TARGET_RDA/TARGET_UNO_91H/lib/CMakeLists.txt
index 6e83093..3f0d69f 100644
--- a/connectivity/drivers/emac/TARGET_RDA_EMAC/lwip-wifi/arch/TARGET_RDA/TARGET_UNO_91H/lib/CMakeLists.txt
+++ b/connectivity/drivers/emac/TARGET_RDA_EMAC/lwip-wifi/arch/TARGET_RDA/TARGET_UNO_91H/lib/CMakeLists.txt
@@ -1,4 +1,4 @@
-# Copyright (c) 2020 ARM Limited. All rights reserved.
+# Copyright (c) 2020-2021 ARM Limited. All rights reserved.
 # SPDX-License-Identifier: Apache-2.0
 
 function(_mbed_get_lib_file_uno_91h)
@@ -6,8 +6,6 @@
         set(LIB_FILE TOOLCHAIN_GCC_ARM/libwifi_sta_ap.a)
     elseif(${MBED_TOOLCHAIN} STREQUAL "ARM")
         set(LIB_FILE TOOLCHAIN_ARM_STD/libwifi_sta_ap.ar)
-    elseif(${MBED_TOOLCHAIN} STREQUAL "IAR")
-        set(LIB_FILE TOOLCHAIN_IAR/libwifi_sta_ap.a)
     endif()
     target_sources(mbed-emac PRIVATE ${LIB_FILE})
 endfunction()
diff --git a/connectivity/drivers/mbedtls/FEATURE_CRYPTOCELL310/TARGET_MCU_NRF52840/CMakeLists.txt b/connectivity/drivers/mbedtls/FEATURE_CRYPTOCELL310/TARGET_MCU_NRF52840/CMakeLists.txt
index 9c043cb..0b0e1d3 100644
--- a/connectivity/drivers/mbedtls/FEATURE_CRYPTOCELL310/TARGET_MCU_NRF52840/CMakeLists.txt
+++ b/connectivity/drivers/mbedtls/FEATURE_CRYPTOCELL310/TARGET_MCU_NRF52840/CMakeLists.txt
@@ -1,4 +1,4 @@
-# Copyright (c) 2020 ARM Limited. All rights reserved.
+# Copyright (c) 2020-2021 ARM Limited. All rights reserved.
 # SPDX-License-Identifier: Apache-2.0
 
 if(${MBED_TOOLCHAIN} STREQUAL "GCC_ARM")
@@ -7,9 +7,6 @@
 elseif(${MBED_TOOLCHAIN} STREQUAL "ARM")
     set(LIBCC_310_EXT TOOLCHAIN_ARM/libcc_310_ext.ar)
     set(LIBCC_310_TRNG TOOLCHAIN_ARM/libcc_310_trng.ar)
-elseif(${MBED_TOOLCHAIN} STREQUAL "IAR")
-    set(LIBCC_310_EXT TOOLCHAIN_IAR/lib_cc310_ext.a)
-    set(LIBCC_310_TRNG TOOLCHAIN_IAR/lib_cc310_trng.a)
 endif()
 
 target_include_directories(mbed-mbedtls-cryptocell310
diff --git a/connectivity/drivers/mbedtls/FEATURE_CRYPTOCELL310/binaries/CMakeLists.txt b/connectivity/drivers/mbedtls/FEATURE_CRYPTOCELL310/binaries/CMakeLists.txt
index 2052eaa..da904ab 100644
--- a/connectivity/drivers/mbedtls/FEATURE_CRYPTOCELL310/binaries/CMakeLists.txt
+++ b/connectivity/drivers/mbedtls/FEATURE_CRYPTOCELL310/binaries/CMakeLists.txt
@@ -1,12 +1,10 @@
-# Copyright (c) 2020 ARM Limited. All rights reserved.
+# Copyright (c) 2020-2021 ARM Limited. All rights reserved.
 # SPDX-License-Identifier: Apache-2.0
 
 if(${MBED_TOOLCHAIN} STREQUAL "GCC_ARM")
     set(LIBCC_310_CORE TOOLCHAIN_GCC_ARM/libcc_310_core.a)
 elseif(${MBED_TOOLCHAIN} STREQUAL "ARM")
     set(LIBCC_310_CORE TOOLCHAIN_ARM/libcc_310_core.ar)
-elseif(${MBED_TOOLCHAIN} STREQUAL "IAR")
-    set(LIBCC_310_CORE TOOLCHAIN_IAR/lib_cc310_ext.a)
 endif()
 
 target_link_libraries(mbed-mbedtls-cryptocell310
diff --git a/platform/source/TARGET_CORTEX_M/CMakeLists.txt b/platform/source/TARGET_CORTEX_M/CMakeLists.txt
index 3ae9a0b..481d09b 100644
--- a/platform/source/TARGET_CORTEX_M/CMakeLists.txt
+++ b/platform/source/TARGET_CORTEX_M/CMakeLists.txt
@@ -1,22 +1,11 @@
-# Copyright (c) 2020 ARM Limited. All rights reserved.
+# Copyright (c) 2020-2021 ARM Limited. All rights reserved.
 # SPDX-License-Identifier: Apache-2.0
 
-
-function(_mbed_set_assembly_source)
-    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)
-    elseif(${MBED_TOOLCHAIN} STREQUAL "IAR")
-        target_sources(mbed-core
-            INTERFACE
-                TOOLCHAIN_IAR/except.S
-                TOOLCHAIN_IAR/cmain.S
-        )
-    endif()
-endfunction()
-
-_mbed_set_assembly_source()
+if(${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
diff --git a/targets/TARGET_STM/TARGET_STM32L4/TARGET_STM32L475xG/CMakeLists.txt b/targets/TARGET_STM/TARGET_STM32L4/TARGET_STM32L475xG/CMakeLists.txt
index e31f393..e9f865d 100644
--- a/targets/TARGET_STM/TARGET_STM32L4/TARGET_STM32L475xG/CMakeLists.txt
+++ b/targets/TARGET_STM/TARGET_STM32L4/TARGET_STM32L475xG/CMakeLists.txt
@@ -1,4 +1,4 @@
-# Copyright (c) 2020 ARM Limited. All rights reserved.
+# Copyright (c) 2020-2021 ARM Limited. All rights reserved.
 # SPDX-License-Identifier: Apache-2.0
 
 add_subdirectory(TARGET_DISCO_L475VG_IOT01A EXCLUDE_FROM_ALL)
@@ -9,9 +9,6 @@
 elseif(${MBED_TOOLCHAIN} STREQUAL "ARM")
     set(STARTUP_FILE TOOLCHAIN_ARM/startup_stm32l475xx.S)
     set(LINKER_FILE TOOLCHAIN_ARM/stm32l475xg.sct)
-elseif(${MBED_TOOLCHAIN} STREQUAL "IAR")
-    set(STARTUP_FILE TOOLCHAIN_IAR/startup_stm32l475xx.S)
-    set(LINKER_FILE TOOLCHAIN_IAR/stm32l475xg.icf)
 endif()
 
 add_library(mbed-stm32l475xg INTERFACE)