Can't lock ModBlocks.java file in 1.17 snapshot

So the 1.17 snapshot uses init java files, one of which is the ModBlocks.java
This is also the file that includes this event to register render layers:

public static void clientSetup(FMLClientSetupEvent event) {
			WhateverBlock.registerRenderLayer();
		}

But for some reason, you can't lock this file, even if you lock the base mod files, so now I am failing at adding a block to this event which I'd need to have the texture be multilayered
Any help?