diff --git a/internal/rosa/cmake.go b/internal/rosa/cmake.go
index 13ad917..8d7129a 100644
--- a/internal/rosa/cmake.go
+++ b/internal/rosa/cmake.go
@@ -97,7 +97,7 @@ func (t Toolchain) NewViaCMake(
 	}
 
 	sourcePath := AbsUsrSrc.Append(name)
-	return t.New(name+"-"+variant+"-"+version, attr.Flag, stage3Concat(t, extra,
+	return t.New(name+"-"+variant+"-"+version, attr.Flag, stage0Concat(t, extra,
 		t.Load(CMake),
 		t.Load(Ninja),
 	), nil, slices.Concat([]string{
diff --git a/internal/rosa/llvm.go b/internal/rosa/llvm.go
index a5e375f..9a85bf5 100644
--- a/internal/rosa/llvm.go
+++ b/internal/rosa/llvm.go
@@ -160,7 +160,7 @@ ln -s ld.lld /work/system/bin/ld
 			[2]string{"LIBCXX_USE_COMPILER_RT", "ON"},
 		)
 
-		if t > toolchainStage3 {
+		if t > toolchainStage0 {
 			// libcxxabi fails to compile if c++ headers not prefixed in /usr
 			// is found by the compiler, and doing this is easier than
 			// overriding CXXFLAGS; not using mv here to avoid chown failures
@@ -199,7 +199,7 @@ cp -r /system/include /usr/include && rm -rf /system/include
 
 		Paths: attr.paths,
 		Flag:  TExclusive,
-	}, stage3Concat(t, attr.extra,
+	}, stage0Concat(t, attr.extra,
 		t.Load(Libffi),
 		t.Load(Python),
 		t.Load(Perl),
@@ -233,7 +233,7 @@ func (t Toolchain) newLLVM() (musl, compilerRT, runtimes, clang pkg.Artifact) {
 	}
 
 	compilerRT = t.newLLVMVariant("compiler-rt", &llvmAttr{
-		env: stage3ExclConcat(t, []string{},
+		env: stage0ExclConcat(t, []string{},
 			"LDFLAGS="+earlyLDFLAGS(false),
 		),
 		cmake: [][2]string{
@@ -276,7 +276,7 @@ ln -s \
 
 	musl = t.NewMusl(&MuslAttr{
 		Extra: []pkg.Artifact{compilerRT},
-		Env: stage3ExclConcat(t, []string{
+		Env: stage0ExclConcat(t, []string{
 			"CC=clang",
 			"LIBCC=/system/lib/clang/21/lib/" +
 				triplet() + "/libclang_rt.builtins.a",
@@ -288,7 +288,7 @@ ln -s \
 	})
 
 	runtimes = t.newLLVMVariant("runtimes", &llvmAttr{
-		env: stage3ExclConcat(t, []string{},
+		env: stage0ExclConcat(t, []string{},
 			"LDFLAGS="+earlyLDFLAGS(false),
 		),
 		flags: llvmRuntimeLibunwind | llvmRuntimeLibcxx | llvmRuntimeLibcxxABI,
@@ -308,7 +308,7 @@ ln -s \
 
 	clang = t.newLLVMVariant("clang", &llvmAttr{
 		flags: llvmProjectClang | llvmProjectLld,
-		env: stage3ExclConcat(t, []string{},
+		env: stage0ExclConcat(t, []string{},
 			"CFLAGS="+earlyCFLAGS,
 			"CXXFLAGS="+earlyCXXFLAGS(),
 			"LDFLAGS="+earlyLDFLAGS(false),
diff --git a/internal/rosa/make.go b/internal/rosa/make.go
index c1c90bc..f330a0a 100644
--- a/internal/rosa/make.go
+++ b/internal/rosa/make.go
@@ -36,8 +36,8 @@ type MakeAttr struct {
 
 	// Do not include default extras.
 	OmitDefaults bool
-	// Dependencies not provided by stage3.
-	NonStage3 []pkg.Artifact
+	// Dependencies not provided by stage0.
+	NonStage0 []pkg.Artifact
 
 	// Additional environment variables.
 	Env []string
@@ -148,8 +148,8 @@ func (t Toolchain) NewViaMake(
 		panic("cannot remain in root")
 	}
 
-	return t.New(name+"-"+version, attr.Flag, stage3Concat(t,
-		attr.NonStage3,
+	return t.New(name+"-"+version, attr.Flag, stage0Concat(t,
+		attr.NonStage0,
 		finalExtra...,
 	), nil, attr.Env, scriptEarly+`
 /usr/src/`+name+`/configure \
diff --git a/internal/rosa/mksh.go b/internal/rosa/mksh.go
index ffef8e5..318bd3c 100644
--- a/internal/rosa/mksh.go
+++ b/internal/rosa/mksh.go
@@ -7,7 +7,7 @@ func (t Toolchain) newMksh() pkg.Artifact {
 		version  = "59c"
 		checksum = "0Zj-k4nXEu3IuJY4lvwD2OrC2t27GdZj8SPy4DoaeuBRH1padWb7oREpYgwY8JNq"
 	)
-	return t.New("mksh-"+version, 0, stage3Concat(t, []pkg.Artifact{},
+	return t.New("mksh-"+version, 0, stage0Concat(t, []pkg.Artifact{},
 		t.Load(Perl),
 		t.Load(Coreutils),
 	), nil, []string{
diff --git a/internal/rosa/musl.go b/internal/rosa/musl.go
index 7848722..7967837 100644
--- a/internal/rosa/musl.go
+++ b/internal/rosa/musl.go
@@ -42,7 +42,7 @@ rmdir -v /work/lib
 		script = ""
 	}
 
-	return t.New("musl-"+version, 0, stage3Concat(t, attr.Extra,
+	return t.New("musl-"+version, 0, stage0Concat(t, attr.Extra,
 		t.Load(Make),
 		t.Load(Coreutils),
 	), nil, slices.Concat([]string{
diff --git a/internal/rosa/rosa.go b/internal/rosa/rosa.go
index 9e54fae..c92928f 100644
--- a/internal/rosa/rosa.go
+++ b/internal/rosa/rosa.go
@@ -82,11 +82,11 @@ func earlyLDFLAGS(static bool) string {
 	return s
 }
 
-// earlyCFLAGS is reference CFLAGS for the stage3 toolchain.
+// earlyCFLAGS is reference CFLAGS for the stage0 toolchain.
 const earlyCFLAGS = "-Qunused-arguments " +
 	"-isystem/system/include"
 
-// earlyCXXFLAGS returns reference CXXFLAGS for the stage3 toolchain
+// earlyCXXFLAGS returns reference CXXFLAGS for the stage0 toolchain
 // corresponding to [runtime.GOARCH].
 func earlyCXXFLAGS() string {
 	return "--start-no-unused-arguments " +
@@ -105,12 +105,12 @@ const (
 	// binary distribution. This is for decompressing unsupported formats.
 	toolchainBusybox Toolchain = iota
 
-	// toolchainStage3 denotes the Gentoo stage3 toolchain. Special care must be
-	// taken to compile correctly against this toolchain.
-	toolchainStage3
+	// toolchainStage0 denotes the stage0 toolchain. Special care must be taken
+	// to compile correctly against this toolchain.
+	toolchainStage0
 
 	// toolchainIntermediate denotes the intermediate toolchain compiled against
-	// toolchainStage3. This toolchain should be functionally identical to [Std]
+	// toolchainStage0. This toolchain should be functionally identical to [Std]
 	// and is used to bootstrap [Std].
 	toolchainIntermediate
 
@@ -122,19 +122,19 @@ const (
 	_toolchainEnd
 )
 
-// stage3Concat concatenates s and values. If the current toolchain is
-// toolchainStage3, stage3Concat returns s as is.
-func stage3Concat[S ~[]E, E any](t Toolchain, s S, values ...E) S {
-	if t == toolchainStage3 {
+// stage0Concat concatenates s and values. If the current toolchain is
+// toolchainStage0, stage0Concat returns s as is.
+func stage0Concat[S ~[]E, E any](t Toolchain, s S, values ...E) S {
+	if t == toolchainStage0 {
 		return s
 	}
 	return slices.Concat(s, values)
 }
 
-// stage3ExclConcat concatenates s and values. If the current toolchain is not
-// toolchainStage3, stage3ExclConcat returns s as is.
-func stage3ExclConcat[S ~[]E, E any](t Toolchain, s S, values ...E) S {
-	if t == toolchainStage3 {
+// stage0ExclConcat concatenates s and values. If the current toolchain is not
+// toolchainStage0, stage0ExclConcat returns s as is.
+func stage0ExclConcat[S ~[]E, E any](t Toolchain, s S, values ...E) S {
+	if t == toolchainStage0 {
 		return slices.Concat(s, values)
 	}
 	return s
@@ -208,7 +208,7 @@ func (t Toolchain) New(
 		args[0] = "hush"
 		env = fixupEnviron(env, nil, "/system/bin")
 
-	case toolchainStage3:
+	case toolchainStage0:
 		name += "-boot"
 		var seed string
 		switch runtime.GOARCH {
@@ -224,11 +224,11 @@ func (t Toolchain) New(
 		args[0] = "bash"
 		support = slices.Concat([]pkg.Artifact{
 			cureEtc{},
-			toolchainBusybox.New("stage3", 0, nil, nil, nil, `
-tar -C /work -xf /usr/src/stage3.tar.xz
+			toolchainBusybox.New("stage0", 0, nil, nil, nil, `
+tar -C /work -xf /usr/src/stage0.tar.xz
 rm -rf /work/dev/ /work/proc/
 ln -vs ../usr/bin /work/bin
-`, pkg.Path(AbsUsrSrc.Append("stage3.tar.xz"), false,
+`, pkg.Path(AbsUsrSrc.Append("stage0.tar.xz"), false,
 				pkg.NewHTTPGet(
 					nil, "https://basement.gensokyo.uk/seed/"+seed,
 					mustDecode(seed),
@@ -328,7 +328,7 @@ cat /usr/src/` + name + `-patches/* | \
 `
 		aname += "-patched"
 	}
-	return t.New(aname, 0, stage3Concat(t, []pkg.Artifact{},
+	return t.New(aname, 0, stage0Concat(t, []pkg.Artifact{},
 		t.Load(Patch),
 	), nil, nil, script, paths...)
 }
diff --git a/internal/rosa/toybox.go b/internal/rosa/toybox.go
index 8db20b7..2e4d470 100644
--- a/internal/rosa/toybox.go
+++ b/internal/rosa/toybox.go
@@ -7,13 +7,13 @@ func (t Toolchain) newToybox(suffix, script string) pkg.Artifact {
 		version  = "0.8.13"
 		checksum = "rZ1V1ATDte2WeQZanxLVoiRGdfPXhMlEo5-exX-e-ml8cGn9qOv0ABEUVZpX3wTI"
 	)
-	return t.New("toybox-"+version+suffix, TEarly, stage3Concat(t, []pkg.Artifact{},
+	return t.New("toybox-"+version+suffix, TEarly, stage0Concat(t, []pkg.Artifact{},
 		t.Load(Make),
 		t.Load(Bash),
 		t.Load(Gzip),
 
 		t.Load(KernelHeaders),
-	), nil, stage3Concat(t, []string{},
+	), nil, stage0Concat(t, []string{},
 		"ROSA_CHECK=make USER=cure tests",
 	), `
 ln -s ../system/bin/bash /bin/ || true