diff --git a/path.go b/path.go
index 338ac68..3e5219b 100644
--- a/path.go
+++ b/path.go
@@ -18,9 +18,6 @@ func ParseBlockID(id string) []byte {
 			if len(part) != 1 {
 				return nil
 			}
-			if _, ok := slotRegistry[part[0]]; !ok {
-				return nil
-			}
 			slots = append(slots, part[0])
 		} else {
 			if part == "" {
diff --git a/path_test.go b/path_test.go
index e80df1e..d545b28 100644
--- a/path_test.go
+++ b/path_test.go
@@ -178,12 +178,12 @@ func TestParseBlockID(t *testing.T) {
 		{"C-0-C-1", []byte{'C', 'C'}},
 		{"H-0", []byte{'H'}},
 		{"C-0-C-0-C-0", []byte{'C', 'C', 'C'}},
+		{"X-0", []byte{'X'}},
+		{"H-0-X-0", []byte{'H', 'X'}},
 		{"", nil},
 		{"L-1-C-0", []byte{'L', 'C'}},
 		{"L-0-C", nil},
 		{"LL-0", nil},
-		{"X-0", nil},
-		{"H-0-X-0", nil},
 	}
 
 	for _, tt := range tests {