diff --git a/filesystem/filesystem.go b/filesystem/filesystem.go
index 1e816a7..8c59df3 100644
--- a/filesystem/filesystem.go
+++ b/filesystem/filesystem.go
@@ -198,6 +198,10 @@
 	unknown
 )
 
+func (fs fsType) IsUnknown() bool {
+	return fs == unknown
+}
+
 type FilesystemInfo struct {
 	// A text file containing the list of paths installed on the partition.
 	FileListFile android.Path
@@ -205,8 +209,7 @@
 
 var FilesystemProvider = blueprint.NewProvider[FilesystemInfo]()
 
-func (f *filesystem) fsType(ctx android.ModuleContext) fsType {
-	typeStr := proptools.StringDefault(f.properties.Type, "ext4")
+func GetFsTypeFromString(ctx android.EarlyModuleContext, typeStr string) fsType {
 	switch typeStr {
 	case "ext4":
 		return ext4Type
@@ -217,11 +220,19 @@
 	case "cpio":
 		return cpioType
 	default:
-		ctx.PropertyErrorf("type", "%q not supported", typeStr)
 		return unknown
 	}
 }
 
+func (f *filesystem) fsType(ctx android.ModuleContext) fsType {
+	typeStr := proptools.StringDefault(f.properties.Type, "ext4")
+	fsType := GetFsTypeFromString(ctx, typeStr)
+	if fsType == unknown {
+		ctx.PropertyErrorf("type", "%q not supported", typeStr)
+	}
+	return fsType
+}
+
 func (f *filesystem) installFileName() string {
 	return f.BaseModuleName() + ".img"
 }