diff --git a/.cargo/config.toml b/.cargo/config.toml
new file mode 100644
index 0000000000..20b285dc57
--- /dev/null
+++ b/.cargo/config.toml
@@ -0,0 +1,2 @@
+[unstable]
+json-target-spec = true
diff --git a/Makefile b/Makefile
index 24bff8a48c..c4807317d8 100644
--- a/Makefile
+++ b/Makefile
@@ -31,12 +31,12 @@ TARGET_SPEC=$(RUST_TARGET_PATH)/$(ARCH)-unknown-kernel.json
 KERNEL_CARGO_FEATURES?=
 
 $(BUILD)/kernel.all: $(LD_SCRIPT) $(LOCKFILE) $(MANIFEST) $(TARGET_SPEC) $(shell find $(SOURCE) -name "*.rs" -type f)
-	cargo -Zunstable-options rustc \
+	cd $(SOURCE) && RUSTUP_TOOLCHAIN=nightly-2025-10-03 cargo rustc \
+		-Z build-std=core,alloc -Zbuild-std-features=compiler-builtins-mem \
 		--bin kernel \
 		--manifest-path "$(MANIFEST)" \
 		--target "$(TARGET_SPEC)" \
 		--release \
-		-Z build-std=core,alloc -Zbuild-std-features=compiler-builtins-mem -Z json-target-spec \
 		--features=$(KERNEL_CARGO_FEATURES) \
 		-- \
 		-C link-arg=-T -Clink-arg="$(LD_SCRIPT)" \
@@ -62,5 +62,5 @@ check:
 		--bin kernel \
 		--manifest-path "$(MANIFEST)" \
 		--target "$(TARGET_SPEC)" \
-		-Z build-std=core,alloc -Zbuild-std-features=compiler-builtins-mem -Z json-target-spec \
+		-Z build-std=core,alloc -Zbuild-std-features=compiler-builtins-mem -Z target-spec-json \
 		--features=$(KERNEL_CHECK_FEATURES)