diff --git a/build/GenerateDef.zig b/build/GenerateDef.zig
index 193db5ac..0814e64c 100644
--- a/build/GenerateDef.zig
+++ b/build/GenerateDef.zig
@@ -53,7 +53,7 @@ fn make(step: *Step, prog_node: *std.Progress.Node) !void {
     // non-backwards-compatible way.
     man.hash.add(@as(u32, 0xDCC14144));
 
-    const contents = try std.fs.cwd().readFileAlloc(arena, self.path, std.math.maxInt(u32));
+    const contents = try b.build_root.handle.readFileAlloc(arena, self.path, std.math.maxInt(u32));
     man.hash.addBytes(contents);
 
     const out_name = b.fmt("{s}.zig", .{std.fs.path.stem(self.path)});