diff --git a/mk/x86-unknown-none.mk b/mk/x86-unknown-none.mk
index 16e949de93..7071d8738b 100644
--- a/mk/x86-unknown-none.mk
+++ b/mk/x86-unknown-none.mk
@@ -7,7 +7,7 @@ all: $(BUILD)/bootloader.bin
 
 $(BUILD)/libbootloader.a: $(SOURCE)/Cargo.toml $(SOURCE)/Cargo.lock $(shell find $(SOURCE)/src -type f)
 	mkdir -p "$(BUILD)"
-	env RUSTFLAGS="--cfg aes_force_soft" \
+	env RUSTFLAGS="--cfg aes_force_soft -Zunstable-options" \
 	cargo rustc \
 		--manifest-path="$<" \
 		-Z build-std=core,alloc \
@@ -20,7 +20,7 @@ $(BUILD)/libbootloader.a: $(SOURCE)/Cargo.toml $(SOURCE)/Cargo.lock $(shell find
 
 $(BUILD)/libbootloader-live.a: $(SOURCE)/Cargo.toml $(SOURCE)/Cargo.lock $(shell find $(SOURCE)/src -type f)
 	mkdir -p "$(BUILD)"
-	env RUSTFLAGS="--cfg aes_force_soft" \
+	env RUSTFLAGS="--cfg aes_force_soft -Zunstable-options" \
 	cargo rustc \
 		--manifest-path="$<" \
 		-Z build-std=core,alloc \