chain with "$macros" does not work anymore

[robinsmidsrod]

I think the uristring encoder has been removed in recent versions of iPXE, as it should no longer be needed with the new URL parser. Do you get the same problem if you just use ${username} in your URL? Are you also sure that the username/password variables actually contain data? I'm assuming you didn't press ESC at the login prompt. What does the URL look like in your web server access log?