diff --git a/sdk_container/src/third_party/coreos-overlay/profiles/coreos/arm64/make.defaults b/sdk_container/src/third_party/coreos-overlay/profiles/coreos/arm64/make.defaults
index e69de29bb2..94b0ffe8f7 100644
--- a/sdk_container/src/third_party/coreos-overlay/profiles/coreos/arm64/make.defaults
+++ b/sdk_container/src/third_party/coreos-overlay/profiles/coreos/arm64/make.defaults
@@ -0,0 +1,2 @@
+# platform "pc" is not supported for target CPU "arm64"
+GRUB_PLATFORMS="efi-64"
diff --git a/sdk_container/src/third_party/coreos-overlay/profiles/coreos/targets/sdk/make.defaults b/sdk_container/src/third_party/coreos-overlay/profiles/coreos/targets/sdk/make.defaults
index 9577fb9179..7121574d1c 100644
--- a/sdk_container/src/third_party/coreos-overlay/profiles/coreos/targets/sdk/make.defaults
+++ b/sdk_container/src/third_party/coreos-overlay/profiles/coreos/targets/sdk/make.defaults
@@ -4,9 +4,6 @@ USE="man -pam"
 # TODO: clean up that old goo
 CROS_SDK_HOST="cros-sdk-host"
 
-# Enable our assorted GRUB targets
-GRUB_PLATFORMS="efi-64 pc xen"
-
 # Enable CPU architectures needed by Rust builds
 LLVM_TARGETS="X86 AArch64"