diff --git a/scripts/fuzz.sh b/scripts/fuzz.sh
index d5fefa98abb5..fa01d8b099b2 100755
--- a/scripts/fuzz.sh
+++ b/scripts/fuzz.sh
@@ -67,13 +67,18 @@ main()
   : "${TEST_DURATION:=3}"
   : "${FUZZER_STDOUT:=/dev/stdout}" # bashism
 
-  west build -d build-fuzz -b native_posix "$SOF_TOP"/app/ -- \
-    -DCONFIG_ASSERT=y \
-    -DCONFIG_SYS_HEAP_BIG_ONLY=y \
-    -DCONFIG_ZEPHYR_NATIVE_DRIVERS=y \
-    -DCONFIG_ARCH_POSIX_LIBFUZZER=y \
-    -DCONFIG_ARCH_POSIX_FUZZ_TICKS=100 \
-    -DCONFIG_ASAN=y "$@"
+  # Move this to a new fuzz.conf overlay file if it grows bigger
+  local fuzz_configs=(
+    -DCONFIG_ZEPHYR_POSIX=y
+    -DCONFIG_ASSERT=y
+    -DCONFIG_SYS_HEAP_BIG_ONLY=y
+    -DCONFIG_ZEPHYR_NATIVE_DRIVERS=y
+    -DCONFIG_ARCH_POSIX_LIBFUZZER=y
+    -DCONFIG_ARCH_POSIX_FUZZ_TICKS=100
+    -DCONFIG_ASAN=y
+  )
+
+  west build -d build-fuzz -b native_posix "$SOF_TOP"/app/ -- "${fuzz_configs[@]}" "$@"
 
   mkdir -p ./fuzz_corpus
 
diff --git a/src/arch/xtensa/CMakeLists.txt b/src/arch/xtensa/CMakeLists.txt
index c51dd956491b..80e3074b8772 100644
--- a/src/arch/xtensa/CMakeLists.txt
+++ b/src/arch/xtensa/CMakeLists.txt
@@ -12,28 +12,27 @@ elseif(CONFIG_IMX8M)
 	set(platform_folder imx8m)
 elseif(CONFIG_IMX8ULP)
 	set(platform_folder imx8ulp)
+elseif(CONFIG_RENOIR)
+	set(platform_folder amd/renoir)
+elseif(CONFIG_REMBRANDT)
+	set(platform_folder amd/rembrandt)
 elseif(CONFIG_MT8186)
         set(platform_folder mt8186)
 elseif(CONFIG_MT8188)
         set(platform_folder mt8188)
 elseif(CONFIG_MT8195)
 	set(platform_folder mt8195)
+else()
+	message(FATAL_ERROR "Platform not defined, check your Kconfiguration?")
 endif()
 
 set(fw_name ${CONFIG_RIMAGE_SIGNING_SCHEMA})
 
-set(platform_ld_script ${platform_folder}.x)
+# File name without directory
+get_filename_component(_plf_ld_script ${platform_folder} NAME)
+set(platform_ld_script ${_plf_ld_script}.x)
 set(platform_rom_ld_script rom.x)
 
-if(CONFIG_RENOIR)
-	set(platform_folder amd/renoir)
-	set(platform_ld_script renoir.x)
-endif()
-
-if(CONFIG_REMBRANDT)
-	set(platform_folder amd/rembrandt)
-	set(platform_ld_script rembrandt.x)
-endif()
 # includes
 
 # None of these should be included if Zephyr strict headers are used.
diff --git a/src/platform/Kconfig b/src/platform/Kconfig
index d1c13c88a1eb..9ee45422b78a 100644
--- a/src/platform/Kconfig
+++ b/src/platform/Kconfig
@@ -5,7 +5,9 @@ menu "Platform"
 choice
 	prompt "Platform"
 	default ZEPHYR_POSIX if ARCH_POSIX
-	default TIGERLAKE
+	# It's not really 'optional' but no value is much less confusing
+	# than falling back on a totally random value.
+	optional
 
 config TIGERLAKE
 	bool "Build for Tigerlake"
diff --git a/zephyr/CMakeLists.txt b/zephyr/CMakeLists.txt
index 9ca5c053a702..9d92a67db85d 100644
--- a/zephyr/CMakeLists.txt
+++ b/zephyr/CMakeLists.txt
@@ -363,6 +363,9 @@ zephyr_library_sources_ifdef(CONFIG_LIBRARY
 	${SOF_DRIVERS_PATH}/host/ipc.c
 )
 
+if(NOT DEFINED PLATFORM)
+	message(FATAL_ERROR "PLATFORM is not defined, check your Kconfiguration?")
+endif()
 zephyr_include_directories(${SOF_PLATFORM_PATH}/${PLATFORM}/include)
 
 # Mandatory Files used on all platforms.