diff --git a/internal/rosa/rosa.go b/internal/rosa/rosa.go
index 7c23736c..97351f10 100644
--- a/internal/rosa/rosa.go
+++ b/internal/rosa/rosa.go
@@ -10,6 +10,7 @@ import (
 	"strings"
 	"sync"
 	"time"
+	"unsafe"
 
 	"hakurei.app/fhs"
 	"hakurei.app/internal/pkg"
@@ -332,7 +333,7 @@ func (s *S) HasStageEarly() (ok bool) {
 }
 
 // NewPatchedSource returns [pkg.Artifact] of source with patches applied. If
-// passthrough is true, source is returned as is for zero length patches.
+// passthrough is true, source is returned as is for zero-length patches.
 func (t Toolchain) NewPatchedSource(
 	name string,
 	source pkg.Artifact,
@@ -346,29 +347,34 @@ func (t Toolchain) NewPatchedSource(
 	paths := make([]pkg.ExecPath, len(patches)+1)
 	for i, p := range patches {
 		paths[i+1] = pkg.Path(
-			AbsUsrSrc.Append(name+"-patches", p[0]+".patch"), false,
-			pkg.NewFile(p[0]+".patch", []byte(p[1])),
+			fhs.AbsRoot.Append("patches", p[0]), false,
+			pkg.NewFile(p[0], unsafe.Slice(unsafe.StringData(p[1]), len(p[1]))),
 		)
 	}
-	paths[0] = pkg.Path(AbsUsrSrc.Append(name), false, source)
+	paths[0] = pkg.Path(fhs.AbsRoot.Append("src"), false, source)
 
-	aname := name + "-src"
-	script := `
-cp -r /usr/src/` + name + `/. /work/.
+	var buf strings.Builder
+	buf.WriteString(`
+cp -r /src/. /work/.
 chmod -R +w /work && cd /work
-`
+`)
 	if len(paths) > 1 {
-		script += `
-cat /usr/src/` + name + `-patches/* | \
-	patch \
-	-p 1 \
-	--ignore-whitespace
-`
-		aname += "-patched"
+		buf.WriteString(`
+function apply {
+	echo "applying $1"
+	patch -p 1 < "/patches/$1"
+}
+`)
+
+		for _, p := range patches {
+			buf.WriteString("apply '")
+			buf.WriteString(p[0])
+			buf.WriteString("'\n")
+		}
 	}
-	return t.New(aname, 0, t.Append(nil,
+	return t.New(name+"-src", 0, t.Append(nil,
 		_patch,
-	), nil, nil, script, paths...)
+	), nil, nil, buf.String(), paths...)
 }
 
 // helperInPlace is a special directory value for omitting the cd statement.
diff --git a/internal/rosa/state.go b/internal/rosa/state.go
index 2939057d..12a9d9e2 100644
--- a/internal/rosa/state.go
+++ b/internal/rosa/state.go
@@ -1053,7 +1053,7 @@ func (ctx *evalContext) pf(
 			return
 		}
 		attr.Patches = append(attr.Patches, KV{
-			strings.TrimSuffix(filepath.Base(pathname), ".patch"),
+			filepath.Base(pathname),
 			unsafe.String(unsafe.SliceData(p), len(p)),
 		})
 	}